Search

A simplified version of the specific contact resistance measurement scheme of G. K. Reeves [Solid State Electronics 23, 487 (1980)] has been developed. Its applicability to semiconducting diamond is demonstrated using four sample types: epitaxial films doped to mid 1019 acceptors/cm3 on 〈100〉 and 〈110〉 type IIa substrates; type IIb diamonds 0.25 mm thick, and type IIb diamonds thinned to 0.035–0.05 mm thick. The ohmic contacts were based on a solid‐state annealing process using carbide forming metals. The measured specific contact resistance depends mainly on the doping level in the diamond. Measured values ranged from 8×10−6 Ω cm2 for heavily doped films to 1×10−2 Ω cm2 for lightly doped bulk samples. A simple analysis shows that the contacts to highly doped layers are suitable for device applications.

Natural type-IIa diamonds were implanted with either boron alone, carbon alone, or carbon plus boron at 77, 300, or 800 K. van der Pauw resistivity and Hall effect measurements of carrier concentration and mobility were made as a function of temperature to determine the most effective implantation conditions for semiconducting device applications. No measurable dopant incorporation occurs for the 800-K implant. The highest carrier concentration and mobility are observed when the implantation is carried out at 77 K. It is further shown that a significant increase in the hole concentration occurs when carbon is implanted prior to boron. These measurements provide direct confirmation of the theoretical predictions of Prins and co-workers. It is shown, however, that the carbon co-implant results in a decreased hole mobility. A multiple-step, low-temperature boron-ion implantation procedure that used three different implantation energies to produce an approximately uniformly doped p-type layer of about 200 nm thickness (as verified by secondary-ion-mass spectrometry on a separate sample) produced the best combination of carrier concentration and mobility. The resulting doped layer was used in the fabrication of an insulated-gate field-effect transistor that demonstrated current saturation and pinch-off at room temperature.

Several metallization schemes using refractory metals have been demonstrated to produce ohmic contacts to diamond via a solid-state reaction process. This process utilizes existing microelectronic techniques and provides strongly adherent contacts which exhibit low contact resistance. Measurements of the long-term reliability of Mo/Au contacts formed by this process on a type IIb diamond crystal are presented here for the temperature range 450 to 625 deg C. The measurements consist of the resistance between two contacts as a function of isothermal annealing time over time intervals in excess of 130 h in a purified inert ambient. The Mo/Au contacts appeared to be stable and reliable at these high temperatures with no indications of deterioration or degradation of performance.

A natural IIa diamond was implanted with boron ions at a substrate temperature of 80 K. Ohmic contacts (Mo/Au) were formed using a solid‐state reaction process. Van der Pauw resistivity/Hall measurements were taken as a function of temperature from room temperature to nearly 600 °C. Heating to approximately 350 °C was necessary to stabilize resistance values to over 3.4 MΩ/sq and 1.3 MΩ/sq for the unimplanted and implanted sides, respectively, indicating possible hydrogen incorporation into the diamond during annealing of the metallized sample in hydrogen. Comparison of the electrical properties of the implanted and unimplanted sides showed that the boron implant introduced electrically active acceptors.

The origin of the motion of semiconductors during ion mixing was investigated by studying both the temperature and the atomic mass dependence of moving species in the GexSi1−x/Ni and the GexSi1−x/Pd systems. Ion mixing was performed with 280‐keV Ar ions at temperatures between 30 K and room temperature. The atomic mass of the GexSi1−x alloy was adjusted by changing the concentration of Ge in the alloy. In thermally induced reactions, no preferential motion of Si or Ge was observed. During ion mixing, the atomic flux of Si was observed to be enhanced compared to that of Ge. The atomic flux of the sum of Si and Ge to metal decreases with increasing substrate temperature during mixing and with increasing Ge concentration in the GexSi1−x alloy. From the strong atomic mass dependence of the moving species during ion mixing it is concluded that the origin of the motion of semiconductors under ion mixing conditions is due to the effects of secondary recoils.

X‐ray photoemission spectroscopy was used to analyze the oxide grown at low temperature on AuxSi1−x films. It was found that the oxide is stoichiometric SiO2, but is structurally distinct from oxides grown on Si at high temperatures (950 °C). Also, unoxidized Au‐Si atom inclusions were observed in the oxide. The composition of the inclusions is dependent on the initial bulk AuxSi1−x composition.

Low dose ion implantation through the Pt/Si silicon interface prior to annealing has been shown to yield a more planar PtSi/Si interface after annealing. The electrical characteristics of these ion mixed diodes have also been shown to be more uniform from device to device as well as more nearly approaching theoretical performance than conventionally prepared diodes.

To address the shortfall in adequate M&S software that can model a wide range of electromagnetic problems, PEO-DD(X)/PMS 500 commissioned the development of a plan for delivery of a Validated, Integrated, Physics-based Electromagnetic Radiation (VIPER) tool set. Microwave Office was identified as one of the most promising microwave electronics simulation codes and was selected for further development and verification and validation. This report shows a wide range of EM test cases in which Microwave Office simulations included linear passive components, linear active components, nonlinear components, and system-level circuits.

To address the shortfall in M&S software capabilities for modeling radomes of various types, PEO-DD(X)/PMS-500 commissioned the development of a plan to satisfy these needs. FSS M&S was identified as one of the most promising FSS simulation approaches, and was selected for further development. This report presents a summary of the verification and validation of the enhanced FSS M&S code over a wide range of electromagnetic test cases, including infinite and finite structures. The verification and validation of FSS M&S conducted under this study was extensive, and can be considered a significant success. Of the 16 cases investigated, 9 cases have numerical and measured results for comparison. Each test case considered in this V&V effort was selected to verify the performance of FSS M&S for a specific application or to validate the underlying theoretical framework of the M&S package. No example studied produced less than favorable results. Throughout this study, FSS M&S demonstrated that it can accurately predict the performance of a wide range of radome structures. Based on the reported results, FSS M&S has been verified and validated as a capable FSS radome modeling and simulation tool for use within the DD(X) program.

We have used the circular transmission line test structure of Reeves (Solid State Electron, 23 (1980) 487–490) in order to determine the specific contact resistance of various metals to semiconducting diamond. Sample types included highly doped epitaxial films on 〈100〉 and 〈110〉 type IIa substrates, type IIb diamonds 0.25 mm thick, and type IIb diamonds thinned to 0.05 mm in thickness. Metallizations tested include the carbide forming refractory metals Ti and Mo, as well as Al, Ni, Au, Pt, and Pd. Measured specific contact resistances ranged from 2 × 10−5 for contacts to highly doped layers to 1 × 10 −2 Ω cm 2 for contacts to natural bulk type IIb diamonds. Ohmic contact behavior was not observed for non-carbide forming metallizations on lightly doped type IIb diamond, either in the as-deposited state, or after annealing.

Natural type IIa diamonds were implanted with boron at 77 K, using a multiple step, low temperature boron ion implantation procedure to produce an approximately uniformly doped p-type layer of about 200 nm thickness. This layer was used to fabricate metal insulator semiconductor field effect transistor devices operating in the depletion mode, with good uniformity from device to device. Two of the devices were used to fabricate a simple demonstration circuit with a voltage gain of two.

Natural type IIa (insulating) diamonds were implanted at liquid nitrogen temperature with either boron or carbon plus boron. Van der Pauw resistivity and Hall effect measurements as a function of temperature were used to determine the effect of the implantation, in comparison with the unimplanted side of the sample. Implantation with carbon plus boron resulted in a carrier concentration more than an order of magnitude greater than that resulting from implantation with boron alone, but with a much lower hole mobility

An overview of enabling materials technologies required for fabrication of electronic devices on diamond is presented. Emphasis is placed on electronic doping of diamond by boron ion implantation. Van der Pauw resistivity and Hall Effect measurements were used to determine the net carrier concentration, carrier mobility and resistivity of natural and synthetic diamonds implanted under various conditions. The measured results for a range of implantation conditions and post-annealing temperatures are discussed in the context cf a model developed by J.F. Prins1. The requirements placed on ohmic contacts to diamond, and a process for fabricating ohmic contacts, is discussed briefly. Finally, current-voltage characteristics of a simple MISFET fabricated on ion implanted natural diamond are presented and analyzed. 1J.F. Prins, Physical Review B, 38 (1988) 5576.

The recognized need for devices that can perform under severe operating conditions and recent advances in the growth of diamond films at moderate temperatures and low pressures has generated great interest in the exploitation of the many unique properties of diamond for solid state devices. Among these properties are high strength, high thermal conductivity, high band gap energy, high carrier mobility, and high resistance to degradation by exposure to radiation, heat, and corrosives[1,2].

The patterns of accumulation of caesium-137 from water by the tissues and organs of the freshwater teleost, the brown trout (Salmo trutta) are described. Estimates of the biological half-times and steady-state concentrations are derived, using a simple exponential equation. In all tissues and organs examined, other than muscle, the rate processes of the trout fall between those of the plaice and the ray. It is concluded that most of the caesium accumulated by the brown trout from water enters other than by the gut, probably through the gills, but as with plaice and ray, the main source of the caesium, possibly 90%, must come from the food. Despite differences in the levels of accumulation, the ratios of the tissue to blood steady state concentrations are very similar in all three species. The steady state caesium concentration of the blood appears to be directly related to the red blood cell count of the fish.

We present evidence in this study that the moving species of metal-semiconductor (metal-Si and metal-Ge) systems under ion mixing conditions are affected by the implantation damage distribution in the sample in accordance with the inverse Kirkendall effect. The direction of thermal annealing atomic transport appears to play a role in ion mixing as well. When these two factors are in the same direction, only one dominant moving species is observed. When these two factors are in opposite directions, both metal and the semiconductor can contribute to the atomic transport in ion mixing.

Data collected over a period of 15 years for lobsters maintained at 10 °C and weighingfrom < 1·0 to 1200 g have been analysed. Equations have been produced defining the relationships of the cast shell weight, the growth increment at the moult, the inter-moult period and the food intake per moult with the weight of the lobster, and of the growth increment with the food intake. In particular, a growth curve has been derived showing the weight of lobsters, kept at 10 °C, with age. It is suggested that when there is an adequate food supply, the growth increment is a constant proportion of the lobster weight, and that variations in growth rate are achieved by changes in the length of the inter-moult period which, in turn, is mainly dependent upon the temperature of the environment.

The relative importance between the thermodynamical driving force and kinetics in thermal annealing and ion mixing in the thermally activated regime has not been clarified. To probe the role of the thermodynamical driving force in reactions between metals and silicon, the Co‐Si system was chosen for investigation. In general, three silicide phases are formed during thermal annealing of samples consisting of Co thin films deposited on Si substrates, i.e., Co2Si (the first phase to form with a heat of formation, ΔHf=−9 kcal/g atoms), CoSi (ΔHf=−12 kcal/g atoms), and CoSi2 (the last phase to form, with ΔHf=−8.2 kcal/g atoms). Previous experiments have shown that annealing a sample of Si/CoSi/Co converts CoSi into Co2Si instead of a continuous growth of CoSi. This type of reaction is apparently unrelated to the magnitude of the thermodynamical driving force since ΔHf of CoSi is significantly larger than those of Co2Si and CoSi2, but is kinetically restricted instead. Under ion mixing conditions the kinetic re...

The patterns of accumulation of caesium-137 from food by the tissues and organs of a marine teleost, the plaice (Pleuronectes platessa) and a freshwater teleost, the brown trout (Salmo trutta) are described and compared. Estimates of the biological half-times and steady-state concentrations are derived and individual organ intakes calculated. Rate constants are similar to those obtained from the accumulation from water studies. Plaice gut and liver have an 11 % increase and trout gut a 6 % increase in their share of the [137Cs] intake arising from accumulation from food, compared with that arising from the accumulation from water. These increases were balanced by decreases in the muscle share of the intake. The overall absorption of [137Cs] from food was 42% for plaice and 67% for trout.

In this paper, we review the experimental observations of the temperature dependence and the moving species in ion mixing, emphasizing the metal-semiconductor systems. Ion mixing is the combined effect of two components. One component is temperature independent and is primarily due to events in the prompt regime; the other component is temperature dependent and has the characteristics of the associated thermal reactions. The moving species during ion mixing are influenced by collisional effects, either due to secondary recoils, or due to local hot spots, or both. The secondary recoil concept is consistent with experimental observations that the motion of the lighter element in a bilayer sample is enhanced. There is ample evidence that while the athermal regime is caused by particle-solid interactions, thermodynamical forces are important in deciding the magnitude of mixing. In the thermally activated regime, the ion induced reaction product should be influenced by the heats of formation of various compounds. We also indicate areas where satisfactory explanations are not available at present.

The formation of amorphous TiAu alloys is investigated using pulsed ion beam annealing (PIBA). The samples consist of thin multilayers of Ti and Au. It is found that samples with compositions in a two-phase region of the TiAu phase diagram can be rendered amorphous whereas those with compositions corresponding to congruently melting compounds can not. The results suggest that metallic glass formation induced by pulsed ion beam annealing involves melt-quenching. A comparison between ion mixing proccsses and pulsed ion beam annealing is also made. Nous avons etudie la formation d'alliages amorphes TiAu recuits par faisceau ionique pulse. Les echantillons sont composes de films minces multicouches de Ti et Au. Nous avons observie que les films dont la composition entre dans une region biphasee du diagramme de phases peuvent denir amorphes alors que ceux dont la composition coincide avec un point de liquefaction con-gruente restent cristallins. Ces resultats suggerent que la formation de verres metalliques par faisceau ionique pulse impliqne une hypertrempe. Finalement, une comparaison est faite entre les procedes de mixage ionique et de recuit par faisceau d'ions pulse.

INTRODUCTIONThe caesium radionuclides, caesium-137 and caesium-134, are important constituents of aqueous radioactive effluents discharged to the environment of the United Kingdom from fuel re-processing plants and nuclear power stations (Howells, 1966; Mitchell, Harvey & Smith, 1968; Harvey, Baker & Mitchell, 1969). Their accumulation by marine fishes has been the subject of several previous studies, beginning with that of Chipman (1959) who noted that caesium-137 was accumulated in the flesh of the killifish(Fundulus heteroclitus)and that accumulation continued even after a period of 72 days. Similarly, Hiyama & Shimizu (1964) showed that the muscle of the common goby(Acanthobus flaviamus)continued to accumulate caesium-134 from sea water after periods of 30 days. Baptist & Price (1962) have examined the whole body uptake of caesium, by absorption from sea water, in two marine species, the flounder(Paralichthys dentatus)and the Atlantic croaker(Micropogon undulatus), and they also investigated the accumulation, tissue distribution and excretion of caesium-137 in the croaker, the little tuna(Euthynnus alleteratus)and the bluefish(Pomatomus saltatoux), following oral administration of single doses. These authors concluded that the heart, liver and spleen of the croaker absorbed caesium-137 from sea water at a faster rate than the muscle, and that orally administered caesium-137 was rapidly absorbed from the digestive tract. Tissue distributions were similar in the croaker, bluefish and tuna. The retention of caesium-137 in croaker tissue was described as a multiple rate process. In later experiments Hiyama & Shimizu (1969) compared turnover rates in various organs and tissues following uptake from sea water and from single injection experiments, and obtained good agreement between the values from the two methods.

Chemical Relationships Group I: Cholanthrene Derivatives The carcinogenic compounds of the cholanthrene group merit separate consideration on account of their chemical relationship to the cholane (bile acid) class of naturally occurring substances. They are, however, of essentially the same type as the benzanthracene derivatives (see p. 222). Methylcholanthrene was prepared independently by Wieland and Dane (125) and by Cook and Haslewood (35) by dehydrogenation of dehydronorcholene, a pentacyclic hydrocarbon obtained in 1925 by Wieland and Schlichting (126) from the bile acid, deoxycholic acid, by simple chemical transformations. The molecular structure of methylcholanthrene was proved by its degradation by Cook and Haslewood (36) to 5:6-dimethyl-1:2-benzanthraquinone, identical with a specimen prepared synthetically by a method which established its constitution. The synthesis of methylcholanthrene by Fieser and Seligman (51) is in complete harmony with this structure, and the conversion of cholic acid into methylcholanthrene has been reported by Fieser and Newman (48). Cholic acid and deoxycholic acid are the two principal acids of human bile, so that in these reactions we have a comparatively simple chemical transformation of important constituents of the human body into a cancer-producing hydrocarbon related in structure to those already known. The interest of these relationships needs no further emphasis. So far it has not been possible to secure evidence that the production in the body of methylcholanthrene or a related compound is an aetiological factor in human cancer. The parent pentacyclic aromatic hydrocarbon, cholanthrene, has also been synthesised, both in London and at Harvard (38, 53). The biological testing of cholanthrene and methylcholanthrene has shown that these two hydrocarbons are carcinogenic agents of greater potency than any compounds hitherto investigated (7, 33, 122). When painted on the skin of mice in 0.3 per cent benzene solution they produce epitheliomas, the first tumours making their appearance after an average period of 70 to 80 days; on subcutaneous injection into rats and mice (results with mice only have been reported with cholanthrene) sarcomas are produced. Tumours are induced by cholanthrene in a comparatively short time, and it appears that the methyl group of methyl-cholanthrene is of no great significance in determining its carcinogenic potency. The essential structural feature is the pentacyclic system in the molecule.

In an extended investigation of the growth-inhibitory activity of carcinogenic compounds and related substances, over two hundred compounds were tested, including various 5-, 10- and 9:10-substituted benzanthracenes, dimethyl derivatives of anthracene, nitrogenous analogues of 1:2 benzanthracene, benzphenothiazines and dibenzphenothiazines, compounds related to 3:4-benzphenanthrene, dibenzfluorenes, dibenzcarbazoles, dibenzpyrenes, azonaphthalenes and related products, naphthylamines and naphthaquinones, arsenonaphthalenes, derivatives of triphenylethylene, and diphenyl derivatives of indene, $\beta $-$\text{naphthindole}$ and $\beta $-$\text{naphthofuran}$. A striking degree of correspondence was often shown by the inhibitory and carcinogenic activity of closely related compounds (e.g. 5-alkyl benzanthracenes; dibenzfluorenes; dibenzphenanthrenes; $2\colon 2^{\prime}$-$\text{azonaphthalene}$, $2\colon 2^{\prime}$-$\text{diamino-1}$: $1^{\prime}$-$\text{dinaphthyl}$ and 3:4:5:6-dibenzcarbazole). However, no inhibitory activity was observed for certain carcinogenic 10- and 9:10-substituted benzanthracenes. On the other hand, inhibitory activity was noted in a few compounds (e.g. $1\colon 2^{\prime}$-$\text{azonaphthalene)}$ which have yielded few or no tumours in exhaustive tests, and in some of a group of synthetic oestrogenic compounds which, although not carcinogenic in the usual sense, are nevertheless associated with the induction of individual types of tumour under special conditions. The relation between molecular structure and inhibitory activity depends in general upon an optimal degree of molecular complexity and upon certain more specific requirements. Nevertheless, the results obtained with derivatives of triphenylethylene suggest that inhibitory activity may still be shown by compounds diverging widely from the polycyclic structure and possessing only a skeletal resemblance. Diminution of inhibitory effect with increased substituent size was shown in the 5-alkyl benzanthracenes tested, although the same relation does not necessarily obtain for other positions. The influence of the nature of the substituent is seen (for example) in the contrast between 10-methyl-, 10-amino- and 10-cyano-1:2-benzanthracene (inhibitory) and 10-isopropyl-1:2-benzanthracene (inactive). Lastly, numerous experiments indicated that solubilization of an active compound usually entails decrease of activity, although certain apparent exceptions were encountered. In addition to the relationship between inhibitory activity and carcinogenicity, and that between both biological properties and chemical structure, consideration is also given to the mode of production of the inhibitory effect.

The preparation of 16β-piperidino- and -morpholino-17-ketones of C18- and C19-steroids from 16α-bromo-17-ketones is described; reduction gives the corresponding cis-16β-amino-17β-ol the structure of which is confirmed by preparation from the trans-16α-bromo-17β-ol and by infrared spectroscopy. trans-16-Amino-17ols were prepared from cis-16-bromo-17-ols and a 16α,17α-epoxide.

Tests for carcinogenic activity have been carried out with about seventy compounds, mostly new substances specially synthesized for the purpose and related to known carcinogenic compounds. The results support the view that there is a definite association between molecular structure and carcinogenic action; thus in the 3:4-benzphenanthrene series, which has not hitherto been investigated extensively, positions 1 and 2 seem to be the favourable points for substitution. The capacity to produce epithelioma does not always run parallel with the capacity to produce sarcoma. Some preliminary observations are given upon the occurrence of multiple tumours in animals receiving some classes of these compounds; this subject requires much further investigation with animals in which the spontaneous incidence of such tumours is known.

The very rapid progress which has been made recently in the chemistry of the œstrogenic hormones, of which an excellent has been given by Girard (1933) has established that these substances are hydrogenated phenanthrene derivatives containing oxygen in the molecule ( cf . Butenandt, Weidlich, and Thompson, 1933). On the assumption of a biological relationship between these hormones and the sterols and bile acids, an assumption which seems justifiable, although it cannot yet be regarded as rigidly proved, œstrone (= ketohydroxyœstratriene) is probably represented by formula I or II. The present communication describes the examination for œstrogenic properties of a number of condensed carbon-ring compounds of somewhat analogous structure in an attempt to elucidate the molecular conditions necessary for œstrogenic activity. A preliminary account of some of these experiments has already been given (cook, Dodds, and Hewett, 1933; cook and Dodds, 1933). Our investigations have brought to light a number of pure synthetic compounds, of known molecular structure, which show this physiological activity, and in some of the compounds studied the activity is of a very high order. It will be observed that one of two oxygen atoms in œstrone is ketonic and the other hydroxylic. Girard (1933) has suggested that these two types of oxygen-containing groups are biologically equivalent, and our own experiments group but no hydroxyl group, whereas others contain only hydroxyl groups in a similar type of molecule.

Condensation of 2α,3α- and 2β,3β-epoxy-5α-androstanes with secondary cyclic amines gives 2β-amino-3α-ols and 3α-amino-2β-ols respectively; reaction of a 2β-bromo-3α-hydroxy-5α-androstane with the same cyclic amines gives the 2α,3α-epoxide in contrast to the 3α-bromo-2β-hydroxy-isomer, which undergoes substitution without inversion to give the corresponding 3α-amino-2β-ol. The mechanisms of these reactions are discussed. The preparation of 2-morpholino-5α-androst-1-ene-3,17-dione is also described.

The results described below are based upon the examination of the organs, and especially of the livers, of 1004 mice under treatment with, in all, 84 compounds, as follows: The primary object of the investigation was to seek for any evidence of the production of cancer of the bladder by pure chemical compounds, which might throw light upon the occupational incidence of this form of cancer in chemical workers and especially in those handling β-naphthylamine. No tumours of the bladder have been obtained, but some peculiar changes in that organ were produced by 1:29-azonaphthalene, and by no other of the compounds hitherto tested. This result has led to further experiments, now in progress, with other compounds related to 1:29-azonaphthalene. Systematic examination of the livers of animals receiving compounds under test has been carried out since the detection, by one of the authors of the present paper, of neoplastic changes in the livers of mice receiving 3:4:5:6-dibenzcarbazole (Boyland and Brues 1937). Hence a large amount of comparative histologic material has been collected which serves to demonstrate the specificity of action of the very few compounds, out of the 84 named in this paper, which produce any considerable change in the structure of the liver.

This article seeks to establish the evolution of the post-medieval two-part house with its central chimney-bay. Seven East-Anglian buildings have been selected to illustrate this thesis.

Condensation of a 17β-acetoxy-16α,17α-epoxy-5α-androstane with morpholine yields a 17β-morpholino-16-ketone as the major product, contaminated with some isomeric 16β-morpholino-17-ketone; in the presence of water the condensation yields the latter isomer as the major product. An intermediate in these reactions was shown to be a 16α-hydroxy-17-ketone. The mechanisms of these reactions are discussed and also those of the condensations of 16α-acetoxy-17-ketone, 17β-acetoxy-16-ketone, and 17β-hydroxy-16-ketone systems with morpholine to give 16β-morpholino-17-ketones.

We present evidence in this study that the moving species under ion mixing conditions are affected by the implantation damage distribution in the sample. This observation holds for metal‐semiconductor, metal‐metal, and semiconductor‐semiconductor systems. The direction of thermal annealing atomic transport appears to play a role in ion mixing as well. When these two factors are in the same direction, only one dominant moving species is observed. When these two factors are in opposite directions, both constituents can contribute to the atomic transport in ion mixing.

In this letter we report the observation of surface segregation of gold from AuxSi1−x alloys with 0.25

The accuracy of lattice parameter determinations by Read camera x‐ray diffraction is shown to be strongly dependent on camera alignment. Alignment of the Read camera eliminates the main sources of error. Further improvement in analysis was achieved by constructing a collimator with a rectangular cross section. Analysis and testing showed that the rectangular collimator enhances the efficiency, resolution, precision, and peak‐to‐background intensity ratio for x‐ray analysis of thin films using the Read camera.

We have investigated the oxidation behavior of co‐deposited Au‐Si films at low temperatures (∼200 °C). Alloys spanning the Au‐Si phase diagram have been examined. Films with greater than 40 at. % Au were found to oxidize forming SiO2, while films with less than 40 at. % Au were found to be relatively stable in an oxidizing ambient. This phenomenon was used to form Au lines with a self‐passivating SiO2 coating. The resistivity of these lines is estimated to be 6–10 μΩ cm.

Optical waveguides fabricated by argon ion mixing in InGaAs/InP superlattice structures grown by low‐pressure metalorganic chemical vapor deposition are demonstrated for the first time. Implantation of argon ions at ∼400 °C eliminates the need for a high‐temperature post‐anneal to induce the compositional disordering. As‐grown and argon‐implanted samples were studied using x‐ray diffraction and optical absorption measurements. Planar buried rib waveguides operating at a 1.5 μm wavelength are fabricated by selective ion implantation.

We present evidence in this study that the moving species under ion mixing conditions are affected by the implantation damage distribution in the sample. This observation holds for metal-semiconductor, metal-metal and semiconductorsemiconductor systems. The direction of thermal annealing and atomic transport appears to play a role in ion-mixing as well. When these two factors are in the same direction, only one dominant moving species is observed. When these two factors are in opposite directions, both constituents can contribute to the atomic transport in ion mixing.