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Nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) sequence data from eight type specimens of previously described

Mushrooms named Gymnopilus spectabilis and G. junonius have been reported widely in North America on both dead hardwood or dead or living conifers. Based on DNA sequences of the internal transcribed spacer region (ITS) and large ribosomal subunit (LSU), we found that although Gymnopilus junonius (= G. spectabilis s. auct.) is widespread in Europe, South America, and Australia, none of the limited sequences available from North America represent this species. We report five species of this group from North America, including three previously described species, G. luteus, G. subspectabilis, and G. ventricosus, and two new species, Gymnopilus voitkii and Gymnopilus speciosissimus. We recognize a sister species to G. luteus, based on sequences previously reported as G. spectabilis from China, Japan, and the Russian Far East, but, lacking material to describe it as a new species, we give it an informal clade name, /sororiluteus. Another new species in this complex is described from Japan, as Gymnopilus orientispectabilis. Species in this group may be distinguished by their ITS sequences as well as by macro- and micromorphology, substrate, and geography.

Three new species of Gyroporus, one from the southern hemisphere (Gyroporus madagascariensis sp. nov.) and two from the northern hemisphere (Gyroporus borealis sp. nov. and Gyroporus smithii sp. nov.), are described. G. madagascariensis is a brownish bolete currently known from Madagascar; it has a mottled pileus somewhat reminiscent of G. mcnabbii, another species known from the southern hemisphere. G. borealis is known from the northeastern United States and is also recorded from the northwestern United States under planted landscape trees. G. smithii corresponds to an orange-colored species that has often been encountered in the United States west and south of the Appalachian Mountains (east of the Great Plains) and is likely often mistaken for G. borealis, which can display orange coloration. Additionally, this study presents evidence that G. roseialbus Murrill and G. subalbellus Murrill, previously synonymized by Rolf Singer, are in fact distinct species.

Tricholoma foliicola was taxonomically reevaluated based on analyses of the holotype and newly collected materials. Basidiospores of T. foliicola were irregularly ellipsoid, showing a cyanophilic reaction with or without tubercles. Phylogenetic analyses of the internal transcribed spacer (ITS) and large subunit 28S regions of the fungal nuclear ribosomal RNA gene demonstrated that T. foliicola is a species of Gerhardtia characterized by irregularly shaped basidiospores. Thus, we transferred this species to Gerhardtia foliicola comb. nov. Cultured mycelia of G. foliicola on malt extract agar medium produced cystidia covered with granules and abundant thallic conidia (arthroconidia), with both schizolytic and rhexolytic secession.

Enokipodins are antimicrobial sesquiterpenes produced by

Enokipodins are antimicrobial sesquiterpenes produced by Flammulina velutipes in a mycelial culture medium. To date, enokipodin production has not been reported in other members of the genus Flammulina. Hence, in this study, the production of enokipodins A, B, C, and D by F. velutipes and F. rossica was investigated. Some strains of F. rossica were confirmed to produce at least one of the four enokipodins in the culture medium. However, some strains of F. velutipes did not produce any of the enokipodins. In an antibacterial assay using liquid medium, enokipodin B showed the strongest growth inhibitory activity against Bacillus subtilis among the four types of enokipodins. Enokipodin B inhibited the spore germination of some plant pathogenic fungi. Enokipodins B and D exerted moderate anti-proliferative activity against some cancer cell lines, and enokipodins A and C inhibited the proliferation of the malarial parasite, Plasmodium falciparum. Productivity of enokipodins of some strains of F. velutipes and F. rossica and antibacterial activity of culture filtrate extract against B. subtilis.

Mycorrhizal fungi were isolated and cultured from rhizomes of mycoheterotrophic Cremastra aphylla (Orchidaceae) plants collected in 3 sites across Japan. In total, 5 Cr. aphylla individuals were collected, and 10 fungal isolates were obtained. Sequence analysis of the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA from the fungal samples revealed that all isolates belonged to the genus Coprinellus in the family Psathyrellaceae. All isolates from each site were of the same phylotype. In total, 3 ITS phylotypes were detected. One of the isolates produced fruiting bodies and was identified as Co. domesticus on the basis of macro- and microscopic characteristics of the basidiomata and ITS sequence data. In this study, the sharing of saprobic Psathyrellaceae fungus by the mycoheterotrophic and leafy Cremastra species was newly confirmed.

Poisonous Entoloma rhodopolium and other similar species including edible E. sarcopum are morphologically diverse. People mistake poisonous species for edible species. Classification and the detection method of these species need to be defined. The morphological and phylogenetic studies have been reported in northern Europe. In Japan, the genetic study remains unsolved. Thus, phylogenetic analysis of E. rhodopolium was conducted using ITS and RPB2 sequences, and the result was compared with that of European species. Japanese E. rhodopolium was classified into three clades, none of which belonged to the true European E. rhodopolium and other known species. Three species were defined as new species. Entoloma rhodopolium clade-I (named E. lacus) was genetically close to but morphologically separated from E. majaloides. Clade-II (E. subrhodopolium) was classified to the same group as E. sinuatum and E. subsinuatum, but distinct from these species. Clade-III was segregated from known Entoloma species including E. lupinum, and named E. pseudorhodopolium. Based on the classification, a simple identification method PCR-RFLP was developed to discriminate between poisonous species and edible E. sarcopum, which is very similar in morphology. The study can help to clarify the taxonomy of complex E. rhodopolium-related species, and to prevent food poisoning.

Gyroporus (Gyroporaceae, Boletales) is a highly diverse genus of poroid ectomycorrhizal mushrooms with a nearly worldwide distribution. Previous attempts to unravel the diversity within this genus proved difficult due to the presence of semicryptic species and ambiguous results from analysis of ribosomal RNA markers. In this study, we employ a combined morphotaxonomic and phylogenetic approach to delimit species and elucidate geographic and evolutionary patterns in Gyroporus. For phylogenetic analyses, the protein-coding genes atp6 (mitochondrial adenosine triphosphate [ATP] synthase subunit 6) and rpb2 (nuclear second largest subunit of RNA polymerase II) were selected based on their utility in studies of Boletales. We infer several distinct clades, most notably one corresponding to G. castaneus as a speciose Northern Hemisphere group, another unifying G. cyanescens and like entities, and a third group unifying G. longicystidiatus and a New World sister species. Also notable is the recovery of a sister relationship between the cyanescens and longicystidiatus clades. We formally describe five new species of Gyroporus, outline a number of provisional species, and briefly discuss distributional patterns. This study provides an important scaffold for future work on this well-known but poorly understood genus of fungi.

The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland.

Panus strigellus was first recorded in Amazonas State of Brazil. This edible mushroom has macroscopic characteristics similar to those of P. lecomtei. In this study, we used evidence obtained from a morphological comparison, molecular analyses and mating tests to clarify the taxonomic status of P. strigellus and show differences compared to the sympatric species of Panus. In addition, this paper discusses and reports some morphological characteristics of P. strigellus. The tetrapolar mating system of P. strigellus and the incompatibility between P. lecomtei and P. strigellus was confirmed. The geographical distributions of both species in the Americas are presented.

Dactylosporina brunneomarginata sp. nov., belonging to the family Physalacriaceae (Agaricales) is described and illustrated. This fungus differs from previously described species of Dactylosporina macroscopically by its viscid pileus and stipe surface when wet, the lamellae with dark brown edges, and microscopically by its gloeocystidioid pileo-, cheilo-, and caulocystidia with olive to yellow-brown oily content. This is the first report on Dactylosporina from Asia.

UNLABELLED PREMISE OF THE STUDY Photosynthetic orchids found in highly shaded forests are often mixotrophic, receiving part of their carbon energy via ectomycorrhizal fungi that had originally received carbohydrate from trees. A photosynthetic orchid, Cremastra appendiculata, is also found under highly shaded forest, but our preliminary data suggested that its associated fungi were not ectomycorrhizal. We tested whether their relation is an unusual example of a mixotrophic orchid associating with saprotrophic fungi by direct detection of fungal DNAs in conjunction with isolation of the fungus in pure culture and experimental inoculation of orchid seeds with the fungus. • METHODS For isolated mycobionts of C. appendiculata plants, two regions of nuclear ribosomal DNA, the internal transcribed spacer (ITS) and the large subunit (LSU), were sequenced, and fruiting bodies of the one isolate, SI1-1 were induced. In addition, two fungal isolates, SI1-1 and KI1-1, were grown in symbiotic cultures with C. appendiculata to verify their status as mycobionts. • KEY RESULTS In phylogenetic analyses, all isolates clustered with fungi belonging to Coprinellus in Psathyrellaceae of Agaricales. Phylogenetic analyses of these DNA sequences showed that five fungal isolates from C. appendiculata, including SI1-1 and two mycobionts isolated from the mycoheterotrophic orchid Epipogium roseum, have very similar ITS sequences. Isolate SI1-1 was identified as Coprinellus domesticus based on the morphological characteristics of the fruiting body. Isolates SI1-1 and KI1-1 induced seed germination of C. appendiculata as mycobionts. • CONCLUSIONS This report is the first of a mycorrhizal symbiosis between a fungus in Psathyrellaceae and a photosynthetic orchid, revealing a new pathway to full mycoheterotrophy and contributing to our understanding of the evolution of mycoheterotrophy.

Genetic variation among 45 Rhizopogon roseolus isolates from 21 different regions of Japan were inferred using amplified fragment length polymorphism (AFLP) markers. Using three primer pair combinations, AFLP analysis reproducibly produced a total of 223 DNA fragments, 74.4% of which were polymorphic. Pairwise dissimilarity of AFLP patterns between isolates ranged from 0.043 to 0.228. Cluster analysis and principal coordinate analysis of AFLP data generally showed four major clusters from geographically distinct areas. The findings suggested that the Japanese populations of R. roseolus from different geographical regions can be distinguished based on AFLP characters.

Porcini (Boletus section Boletus: Boletaceae: Boletineae: Boletales) are a conspicuous group of wild, edible mushrooms characterized by fleshy fruiting bodies with a poroid hymenophore that is ‘‘stuffed’’ with white hyphae when young. Their reported distribution is with ectomycorrhizal plants throughout the Northern Hemisphere. Little progress has been made on the systematics of this group using modern molecular phylogenetic tools because sampling has been limited primarily to European species and the genes employed were insufficient to resolve the phylogeny. We examined the evolutionary history of porcini by using a global geographic sampling of most known species, new discoveries from little explored areas, and multiple genes. We used 78 sequences from the fast-evolving nuclear internal transcribed spacers and are able to recognize 18 reciprocally monophyletic species. To address whether or not porcini form a monophyletic group, we compiled a broadly sampled dataset of 41 taxa, including other members of the Boletineae, and used separate and combined phylogenetic analysis of sequences from the nuclear large subunit ribosomal DNA, the largest subunit of RNA polymerase II, and the mitochondrial ATPase subunit six gene. Contrary to previous studies, our separate and combined phylogenetic analyses support the monophyly of porcini. We also report the discovery of two taxa that expand the known distribution of porcini to Australia and Thailand and have ancient phylogenetic connections to the rest of the group. A relaxed molecular clock analysis with these new taxa dates the origin of porcini to between 42 and 54 million years ago, coinciding with the initial diversification of angiosperms, during the Eocene epoch when the climate was warm and humid. These results reveal an unexpected diversity, distribution, and ancient origin of a group of commercially valuable mushrooms that may provide an economic incentive for conservation and support the hypothesis of a tropical origin of the ectomycorrhizal symbiosis.

Seven species of Mycena are reported as luminescent, representing specimens collected in Belize, Brazil, Dominican Republic, Jamaica, Japan (Bonin Islands), Malaysia (Borneo) and Puerto Rico. Four of them represent new species (Mycena luxaeterna, M. luxarboricola, M. luxperpetua, M. silvaelucens) and three represent new reports of luminescence in previously described species (M. aff. abieticola, M. aspratilis, M. margarita). Mycena subepipterygia is synonymized with M. margarita, and M. chlorinosma is proposed as a possible synonym. Comprehensive descriptions, illustrations, photographs and comparisons with phenetically similar species are provided. A redescription of M. chlorophos, based on analyses of type specimens and recently collected topotypical material, is provided. The addition of these seven new or newly reported luminescent species of Mycena brings the total to 71 known bioluminescent species of fungi.

In this study, genetic variation of Armillaria mellea subsp. nipponica was estimated using intergenic spacer-restriction fragment length polymorphism (IGS-RFLP) and amplified fragment length polymorphism (AFLP) analyses. Four IGS-RFLP phenotypes were produced, of which two have never been reported. AFLP analysis suggested that the 11 isolates used could be divided into five subgroups, and the isolates within the same subgroup were distributed throughout a relatively large area in Japan. A parental isolate and its offspring (single-spore isolates) showed an almost identical AFLP profile to each other. These results suggest that the large distribution of the isolates within the same subgroup were established via the basidiospore from a common parental strain.

Genetic relationships in a natural Japanese population of Pleurocybella porrigens were determined based on ITS sequence data. In a UPGMA similarity tree, all sequences of 23 specimens from 13 different geographic origins were grouped into two distinct clusters (groups A and B). Sequence variation of the ITS region between groups A and B consisted of 33–40 nucleotides, corresponding to 5%–6% of their total length, and specific nucleotide variations characterizing groups A and B were found. Although these results did not show correlation with differences of substrates for fruiting and geographic origins of the specimens, it was suggested that P. porrigens distributed in Japan include at least two genetically different populations.

To estimate the phylogenetic position of Pholiota nameko in the genus Pholiota, restriction fragment length polymorphisms (RFLPs) for PCR products of 26S ribosomal RNA gene (rDNA), internal transcribed spacers (ITS), and intergenic spacer (IGS) of the rDNA repeat from P. nameko and eight of its closely related species were investigated, and a phylogenetic tree was constructed based on data that resulted from RFLP analysis. P. nameko was clustered together with P. adiposa, P. limonella, and P. aurivella of the subgenus Pholiota (section Adiposae). However, P. nameko and P. albocrenulata, both of which belong to the subgenus Hemipholiota, were phylogenetically separated from each other. Our results suggested that P. nameko is closely related to the members of the section Adiposae. Furthermore, the phylogenetic distance between this section Adiposae group including P. nameko and Kuehneromyces mutabillis was smaller than that between P. malicola var. macropoda of the subgenus Flammula and the members of section Adiposae. Our data indicate that molecular information on rDNA will be useful to reconstruct taxa within the genus Pholiota in the family Strophariacea that have been classified mostly on the basis of morphological characters.

Isozyme patterns were examined to characterize biological species ofArmillaria in Japan. Of 25 different enzymes tested, glutamate dehydrogenase (GDH), lactate dehydrogenase (LDH), and aspartate aminotransferase (AAT) showed the most stable and reliable activities. These isozyme patterns showed little variability between haploid and diploid hyphae even under different cultural conditions among isolates tested. From the results, six Japanese biological species were clearly characterized through combination of GDH and LDH isozymes. There were no differences on the whole in isozyme patterns among European biological species ofArmillaria.

During an investigation of Hypocrea/Trichoderma species inhabiting mushroom bedlogs, we found five strains of an undescribed species from a culture collection. These were analyzed using a combined approach, including morphology of holomorph, cultural studies, and phylogenetic analyses of the rRNA gene cluster of the internal transcribed spacer region, translation elongation factor 1-α, and RNA polymerase subunit II gene sequences. Distinctive morphological characters include stromata with green ascospores produced on potato dextrose agar medium, and Gliocladium-like to irregularly Verticillium-like conidiophores. In phylogenetic analyses, this species belongs to the Semiorbis clade, but its morphological characteristics do not match the other members of this clade. Based on morphological observations and phylogenetic analyses, we describe this as a new species, Trichoderma mienum, representing its Hypocrea teleomorph and Trichoderma anamorph.

Combining different chromatography systems, unusual nonprotein amino acids were isolated and unequivocally identified from a small amount (less than 100 g fresh weight) ofAmanita gymnopus fruit body. Without obtaining crystals of these amino acids, on the basis of1H-NMR determination, high resolution mass spectrometry, chlorine analysis and oxidation with L-amino acid oxidase, one of them proved to be a new chloroamino acid, (2S)-2-amino-5-chloro-4-hydroxy-5-hexenoic acid (G2). The other three were (2S)-2-amino-5-hexenoic acid (G1), (2S)-2-amino-4,5-hexadienoic acid (G3) and (2S)-2-amino-5-hexynoic acid (G4). Amino acid (G1) was also encountered for the first time in natural products. Amino acid (G3) has been reported from several kinds of fungi belonging toAmanita, subgenusLepidella. The occurrence of amino acid (G4) was already reported fromCortinarius claricolor.

Boletus hiratsukae, sp. nov. is described and illustrated from Japan. It belongs to section Boletus and is characterized by the fuliginous to dark brown color of both the pileus and stipe, a dry, pruinose-subvelutinous pileus without any rugosity throughout its development, and by a palisade trichodermium structure of the pileipellis in which the element hyphae are often submoniliform with shortened, more or less inflated, terminal and subterminal cells. Data on the habitat suggest that it may form mycorrhizal associations with members of Pinaceae, especially Abies and Pinus.

Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis of the first intergenic region (IGR1) of nuclear ribosomal DNA was used to clarify the relationship between IGR1 variations and six Japanese biological species of Armillaria: A. gallica, A. nabsnona, A. ostoyae, A. cepistipes, A. mellea and Nagasawa's E (Nag. E: taxonomically unknown species). The procedure was then used to identify Armillaria species associated with Wynnea species (W. americana and W. gigantea) and Entoloma abortivum. By combining the RFLP patterns obtained using three endonucleases, HaeIII, HinfI and MspI, the IGR1s from 18 isolates of six Armillaria species were assigned to nine different RFLP phenotypes and the six species were distinguished from each other. Each of the RFLP phenotypes from the Armillaria isolates associated with Wynnea species or E. abortivum matched a corresponding phenotypes observed among the six Armillaria species. Based on this, all four isolates from W. gigantea were identified as A. mellea, two from W. americana as A. cepistipes, and all three from E. abortivum as Nag. E. These results provide new information on the biological species of Armillaria associated with Wynnea and E. abortivum.

Mo-and Ti-silicided junctions were formed using the ITM technique, which consists of ion implantation through metal (ITM) to induce metal-Si interface mixing and subsequent thermal annealing. Double ion implantation, using nondopant ions (Si or Ar) implantation for the metal-Si interface mixing and dopant ion (As or B) implantation for doping, has resulted in ultrashallow ( ≤ 0.1-µm) p+-n or n+-p junctions with ∼30-Ω sheet resistance for Mo-silicided junctions and ∼5.5-Ω sheet resistance for Ti-silicided junctions. The leakage current levels for the Mo-silicided n+-p junctions (0.1-µm junction depth) and the Mo-silicided p+-n junction (0.16-µm junction depth) are comparable to that for unsilicided n+-p junction with greater junction depth ( ∼0.25 µm).

The calculated maximum aspect ratio (depth-to-diameter ratio) for via-hole filling without cavity creation by bias-sputtering, considering the shadowing effect, was found to be in good agreement with the experimental value, which was practically less than 1. The results indicated that reducing the shadowing effect is essential to enable the filling of via-holes with high aspect ratios by a simultaneous deposition and ion etching technique. Partially ionized evaporation was chosen as a technique with little shadowing effect. Experimental results by arc-discharge partially ionized evaporation showed that via-holes with an aspect ratio ∼1 were filled with Mo.

A method of systematic evaluation and determination of host parameters is developed for infrared-to-visible conversion phosphors based on a simple rate equation model. Calculated rise characteristics of the visible emissions are in satisfactory agreement with the experimental results obtained for YF3: Yb, Er phosphors. Several host parameters, such as nonradiative decay rate and energy transfer coefficient, were obtained systematically by fitting the calculated curves with expermental data. It was shown that the conversion efficiency of the infrared light into the green emission is dependent on nonradiative decay rate as well as sensitizer excited state lifetime, both of which are sensitive to preparation procedures. Discussions are presented on the applicability limit of the rate equation model.

Efficient up‐conversion of near‐infrared energy was realized by confinement of infrared energy in an optical cavity containing a BaY2F8 : Yb,Er single crystal. The lifetime of the ytterbium excited state showed a marked increase and, in a typical instance, became as long as 3.6 msec. Combined with 8% efficiency GaAs : Si diode, an over‐all conversion efficiency of nearly 0.04% was obtained for a 50‐mA diode‐exciting current.

A new low resistance shallow junction formation method is described. The new method utilizes extensive dopants lateral diffusion through a metal silicide layer formed between a silicon substrate and an insulating film. This technology enables reversing the process sequence between doping and insulating film deposition, i.e., it enables a doping process after insulating film deposition. MOSFETs with Mo-silicided source/drain and gate and Mo-silicided n+-p junction diodes were fabricated as device application demonstrations of the new technology.

A novel direct contact fabrication technology for Mo gate MOS LSIs has been developed, A feature of the new technology is that the direct contact hole silicon surface is covered with a uniform and thin Mo silicide film, The Mo silicide film was formed with sufficient reproducibility by As implantation through thin (∼100 A) Mo film and subsequent annealings, Mo/Mo silicide/n+-Si direct contact showed remarkable improvement in thermal durability, A high speed 4 K bit static MOS RAM was fabricated using the above-mentioned direct contact technology combined with 1 µm effective channel Mo gate MOS technology.

Electromigration experiments were conducted on sputtered Al-Si alloy films of different metallographical properties, particularly, various grain sizes. The observed failure mode and median time to failure were found to be strongly dependent on grain size and its homogeneity in the films. Results were obtained on temperature dependence of median time to failure and of the failure mode in fine grained films. These failure mode differences were found to be related to void growth directions in conductor stripe, which were dependent on test conditions.

Highly stable (up to 550°C) contacts have been realized in an Al–2%Si contact to n+–p and p+–n shallow junctions (Xj~0.16 µm) covered by a 0.1 µm thick uniform MoSi2 layer, which was formed by the ion implantation through metal ITM technique. Low contact resistance was maintained, at submicron (0.5 µm square) Al–Si/MoSi2 contacts, after 550°C sintering for 30 minutes.

A new low resistance MOS technology has been developed. An essential part of the new technology is ion implantation through metal film (ITM) to induce metal/Si interface mixing and also to form doped layers. The ITM technique enablds forming high quality refractory metal silicide overcoats on Si patterns with excellent self-alignability and reproducibility. Using the new technology, MOSFETs with self-aligned Mo-silicided gate and source/drain have been fabricated, even without any insulating spacers on gate side walls.

Highly stable (up to 550°C) contacts have been realized in an Al–2%Si contact to n +–p and p +–n shallow junctions (X j∼0.16 µm) covered by a 0.1 µm thick uniform MoSi2 layer, which was formed by the ion implantation through metal ITM technique. Low contact resistance was maintained, at submicron (0.5 µm square) Al–Si/MoSi2 contacts, after 550°C sintering for 30 minutes.

Mo-silicides, formed by a new technique combining ion implantation through metal film (ITM) to induce metal/Si interface mixing and also to form doped layers with appropriate subsequent annealings, were found to have excellent properties in film uniformity and self-aligned formation for exposed Si areas (contact holes). These excellent silicidation properties in the ITM technique were also confirmed for patterned poly-Si silicidation. Lateral silicide growth out of contact holes, usually observed in silicidation using mere thermal reaction of refractory-metal/Si structures, was markedly suppressed in the ITM silicidation.

A numerical program to obtain the impurity profile within a semiconductor material from the measured spreading resistance data was developed. In the program, an image method was applied to calculate the spreading resistance of the multilayered structure, which consisted of a stack of layers, each of homogeneous resistivity, with thicknesses equal to the spacing of the spreading resistance data. The solution adopted in the present program is described in this paper. Converting results from the spreading resistance data to the impurity profile of an implanted and diffused sample and buried channel are also shown.

A process of forming electrodes and interconnections in a silicon semiconductor device comprises the steps of forming an insulating film on a silicon substrate, defining an opening in the insulating film, depositing a layer of metal having a high melting point on the insulating film, implanting ions to mix an interface between the metal layer and the silicon substrate, heating the construction in a temperature in the range of from 400 to 650 degrees Celsius to form a silicide of the metal layer in the opening, and selectively etching away an unreacted metal layer so as to self-align the silicide metal layer with the opening. The silicide metal layer is then annealed in a non-reducing gas atmosphere at a temperature ranging from 800 to 1,100 degrees Celsius.

A new angled‐surface‐moving model for surface planarization by rf bias sputtering is proposed. This planarization is achieved by angular selective etching of SiO2 films on top of metal stripes. A two‐step rf bias‐sputtering technique was developed, based on the new model. In this technique, the substrate bias voltage was changed in two steps during bias sputtering. The first step was to fill gaps without microcracks. The second step was to planarize at higher substrate bias. The planarized SiO2 layer surface, deposited on thermally oxidized Si wafers with Mo stripe patterns, had good flatness. A planarized 4‐level metallization test structure was fabricated by the two‐step rf bias‐sputtering.