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In this paper, static measurements and defect analysis performed on InAlAs/InGaAs/InP HFETs are presented. I d – V ds – T , I d – V gs – T and I g – V gs – T characteristics show anomalies (leakage current, degradation in saturation current, kink effect, distortions on I d – V d characteristics in saturation region after high voltage application, …). Deep defects analysis performed by means of capacitance transient spectroscopy (C-DLTS) and frequency dispersion of the output conductance ( G ds ( f )) prove the presence of deep defects with activation energies ranging from 0.12 to 0.75 eV. The presence of generation–recombination centers, acting like traps, is confirmed by I g – V gs . The localization and the identification of these defects are presented. Finally, the correlation between the anomalies observed on output characteristics and defects is discussed.

High-resolution photoinduced transient spectroscopy (HRPITS) has been applied to study the electronic properties of grown-in point defects in semi-insulating (SI) GaAs bulk crystals grown by liquid encapsulated Czochralski (LEC) and vertical gradient freeze (VGF) methods. The novel method, which represents the significant improvement of the earlier PITS technique, relies on the extraction of trap parameters from the digitally recorded photocurrent transients by means of the correlation procedure. The influence of the crystallisation conditions on the defect structure of high resistivity GaAs is compared. In the VGF material the concentrations of traps P6 (0.05 eV), P7 (0.08 eV), P12 (0.18 eV), EL14 (0.22 eV) and EL3 (0.58 eV), tentatively identified as V As −/0 , Ga As 0/− , B As −/−− , V Ga –V As and O i –V As , respectively, are found to be much lower than in the LEC material.

Further evidence was found that the 0.8 eV luminescence band in GaAs is correlated to the EL6 defect as identified by photo induced current transient spectroscopy (PICTS). From luminescence topography arguments are put forward that the EL6 defect should not be the dominant recombination centre in GaAs. By the application of microwave detected PICTS it could be shown that the EL6 is definitely not a relevant recombination centre. Recombination takes place most probably via different, partially not jet identified centres.

Non-destructive and spatially resolved (35 μm) characterisation methods for high resistivity GaAs and epitaxial substrates are presented. Microwave detected photo induced current transient spectroscopy (PICTS) is a further development of the already existing method Microwave detected photoconductivity (MDP). Using various GaAs samples of different preparations, the possibilities of these new tools are demonstrated along with the first results for technologically relevant extrinsic and intrinsic defects.

We review our recent studies on the reactions of hydrogen with transition-metals (Pd, Pt, Ag, and Au) in crystalline Si. Hydrogen was incorporated into the samples by wet-chemical etching. Deep-level transient spectroscopy (DLTS) on Schottky diodes reveals several transition metal‐hydrogen complexes in n- and p-type samples. From DLTS profiling, we are able to estimate the number i of hydrogen atoms in the TM‐Hi complexes. All complexes with i 1, 2 are electrically active. Striking similarities are found for isoelectronic complexes, e.g. Pt‐H2 and Au‐H1. Transition metal complexes with more than three hydrogen atoms are likely to be electrically passive. All hydrogen related complexes disappear after heat treatments above 600 K for several hours. © 1999 Elsevier Science S.A. All rights reserved.

The effect of wet chemical etching and subsequent annealing on the electrical activity of the dislocation-related centers in n-type Si is investigated by the deep-level transient spectroscopy. It is observed that hydrogen penetrates into the samples already during room temperature etching but passivates the dislocation centers only after 300°C annealing. The different dislocation centers exhibit different efficiency of hydrogen passivation. Possible reasons for the observed peculiarities of the dislocation passivation are discussed.

The effect of rapid thermal annealing conditions on the defect levels existing in bulk Si-doped n-GaAs was investigated by deep-level transient spectroscopy. The concentrations of four electron traps at E c −0.36 eV ( T 1) , E c −0.37 eV ( T 2) , E c −0.55 eV ( T 3) and E c −0.75 eV ( T 4) were found to be dependent on the annealing temperature. A large increase in the concentration of trap T1 accompanied by a sharp decrease in the concentration of trap T2 was observed after annealing at 650 °C. As a result of annealing at 750 °C, the concentration of trap T2 rose to the level as before annealing and the trap T3 almost disappeared. A significant drop in the concentration of trap T4 (EL2) was observed after annealing at 850 °C. Simultaneously, the change in the activation energy of the T4 (EL2) centre from 0.75 to 0.55 eV was found. The results are discussed in terms of point defect generation and annihilation and give a new insight into microscopic identity of the traps observed.

Thermally induced metastable electrical activity with buried heteroepitaxial layers in Si/Si(Ge) has been investigated using deep-level transient spectroscopy (DLTS) and temperature-dependent electron-beam-induced current and preferential chemical etching. Examination of diodes located on regions with different misfit dislocation densities on the same wafer indicate that the concentration of the metastable electronic defects decreases with increasing dislocation density. Depth-dependent DLTS reveals two metastable deep level traps, one of which is associated with unrelaxed interfacial strain. A discussion of the possible physical sources of these two defect levels is presented.

Deep levels in undoped semi-insulating In 0.52 Al 0.48 As layers grown by molecular beam epitaxy on iron-doped InP have been studied by photoluminescence and photo-induced current transient spectroscopy. The effect of the growth temperature T g in the range from 300 o C to 530 o C has been investigated. The results show that low T g causes the material quality to deteriorate and leads to formation of a higher concentration of deep traps. It is shown that optimized material quality can be obtained For InAlAs layers on InP substrates with T g around 530 o C with sufficiently high resistivity, reduced trap density and good structural properties which is appropriate for fabrication of high electron mobility transistors

Deep-level transient spectroscopy has been employed for monitoring grown-in point defects in vapour phase epitaxial GaAs0.6P0.4:Te and GaP:N,S. It is shown that the concentrations of deep electron traps T1 (0.20 eV) and T2 (0.18 eV) in GaAs0.6P0.4:Te are dependent on the shallow donor concentration and these traps are tentatively identified as TeAsGaAsTeAs and OiTeAs complexes respectively. The concentrations of 0.24 eV and 0.44 eV electron traps detected in GaP:N,S are dependent on the growth temperature and these traps are attributed to P vacancies and the ((NP)2VGa)− complex respectively.

If p-CdTe crystals are dipped in an AgNO 3 solution followed by storage of the crystals at 300 K, one can observe a strong decrease in the hole concentration after some days. This is obviously due to fast diffusion of silver, which takes place most probably via interstitial sites (Ag i ), and is consistent with the increase in the degree of compensation detected by photoluminescence (PL) analysis. Deep-level transient spectroscopy investigations have shown the appearance of a new hole trap at 0.47 eV after the silver diffusion procedure, which is tentatively assigned to the Ag i deep donors. If the silver treatment is applied to p-CdTe crystals annealed in a tellurium atmosphere, the concentration of Ag Cd impurities grows owing to the defect reaction V Cd +Ag I →Ag Cd as can be seen from the enhancement of the corresponding (A 0 ,X) line in the PL spectra. Positron annihilation measurements with the same crystals have confirmed this reaction by the observation of a decrease in the average positron lifetime before the silver treatment (about 295 ps) to a value of about 285 ps which occurs after some hundred hours. By means of a quantitative PL analysis we are able to estimate the concentration of isolated V Cd in p-CdTe from the increased Ag Cd concentration. Other possible defect reactions are discussed on the basis of our PL investigations.

We have applied the technique of light-beam-induced transient spectroscopy, which characterizes minority carrier capture and emission at point and extended defects, to oxidation-induced stacking faults in n-type silicon. We have compared the minority carrier trap data with conventional deep-level transient spectra for majority carrier traps. We find that we are able to distinguish between hole capture at randomly distributed point defects (e.g Au), and hole capture at point defects which are associated with the extended-defect strain field.

Deep defects produced by high energy, low dose proton implantation into n-type silicon have been investigated by deep-level transient spectroscopy. The complete set of characteristic electrical parameters is given for the induced dominant electron and hole traps after long-term annealing, i.e. energy levels, emission rates and capture cross-sections for majority and minority carriers, which have been determined directly by the pulse width variation technique.

Rhodium, which is believed to favour interstitial diffusion in silicon (corresponding to its high diffusivity), forms levels in the upper half of the silicon band gap which are attributed to a substitutional site. Gold in silicon diffuses mainly via its interstitial component, while the formation of substitutional gold is controlled by a kick-out mechanism creating self-interstitials. We observe a strong enhancement of substitutional gold formation in rhodium-doped samples at low diffusion temperatures which can be understood by assuming a AuRh kick-out reaction. The kinetic behaviour is demonstrated by annealing experiments which are observed by means of deep-level transient spectroscopy.

The detection of thermal emission of captured carriers from deep levels is still considered as the most sensitive way to derive information on the electrically active impurities in semiconductors. To enhance the capabilities of probing thermal emission we are developing a microwave detection technique. The present paper reports on the theoretical description and experimental verification of the functioning of the microwave detection system. The possibilities of this measurement technique in defect studies are illustrated using measurements of the Si:Se0 system.

A scanning minority carrier transient spectroscopy (SMCTS) method with optical injection and full transient analysis is developed to obtain the lateral distribution of electrically active defects. From an appropriate theoretical model and a new signal treatment, the spatial resolution in addition to the shape of the signal are controlled. Influences of non-exponential transients on the final defect distribution can then be determined. Finally the technique is applied to study the gold diffusion along the grain boundary in a silicon bicrystal and yields new results on the nature of gold-related defects.