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This paper is focused on the determination of thermal parameters (thermal conductivity, thermal diffusivity, and specific heat capacity) of electrical insulating paper from various producers. The transient step-wise method was used to determine all thermal parameters simultaneously. Evaluation was carried out using the differential method. Thermal conductivity was determined from the steady-state temperature response on thickness (corresponding to the number of paper layers), while thermal diffusivity and specific heat capacity was obtained from the dependence of derivative maximum and the corresponding temperature on thickness. Four electro insulating papers differing by composition and thickness: materials NKN (Nomex-Kapton-Nomex), DMD (Dacron-Mylar-Dacron), TFT (TufQUIN TFT 50) and TVAR (ThermaVolt AR) were studied. As a result, the highest value of thermal conductivity (0.17 W/m/K) was determined for the DMD. Remaining three materials possessed thermal conductivity about 0.12 W/m/K. However, differences in specific heat capacity and thermal diffusivity were found to be significantly higher. The lowest specific heat capacity was found for the DMD sample (1200 J/kg/K), while the highest specific heat capacity was found for TVAR sample (4000 J/kg/K).

The spectrum of defects produced by 5 MeV electron irradiation in oxygen-lean p-type silicon strongly contaminated with interstitial copper (Cui) is studied using the deep-level transient spectroscopy. It is observed that the room-temperature irradiation creates a large amount of CuPL centers (complexes including one substitutional and three interstitial Cu atoms). The analysis shows that this process is govern by formation of the substitutional copper atoms due to the direct reaction between irradiation-induced vacancies and mobile Cui species. This reaction consumes nearly all irradiation-induced vacancies and affects strongly the standard spectrum of radiation defects.

We investigated annealing behavior of the carrier lifetime and the deep levels in electron irradiated n-type and semi-insulating 4H-SiCs. We observed two peaks for each sample by photo induced current transient spectroscopy (PICTS) measurements, and their heights depended on annealing temperature. By comparing the annealing behavior of the peak height with reported temperature dependence of concentrations of various defects, we speculated that the observed peaks originate from either VSiVC, CSiVC or EI4.

A total of nine electrically active levels have been detected in as-grown and electron irradiated p-type 4H-SiC epilayers. These traps are found in the 0.32-2.26 eV energy range, above the valence band edge (EV). Of these, six are majority carrier traps whereas three are minority carrier traps. We found that thermal oxidation affects the concentrations of two midgap levels, the majority carrier trap, labeled HK4 and the minority carrier trap identified as EH6/7. The analysis of the irradiation energy and dose dependence of the concentration of these two traps, rules out the possibility that they may share the same origin.

Defect levels in high purity semi-insulating 4H silicon carbide substrates are studied by charge transient spectroscopy using 5.5 MeV alpha particles. A shallow defect level with the activation energy around 0.3 eV is found in all samples annealed at temperatures from 1400 to 1600 °C. Some other defect levels lying at deeper in the bandgap are found in samples annealed at 1400 and 1500 °C. As these deep levels are annealed out by 1600 °C, the series resistance of samples is decreased.

Formation and annealing behavior of the 1.014-eV copper center and its dissociation product (center) in silicon are characterized by photoluminescence (PL) and deep-level transient spectroscopy (DLTS) measurements. On the basis of the findings reported in this study, the structures of the centers are discussed.

Temperature dependent capacitance-voltage (C-V) and constant capacitance transient spectroscopy (CCDLTS) measurements have been performed to investigate the role of N in improving the transport properties of 4H-SiC MOS transistors. The higher channel mobility in the N pre-implanted transistors is due at least in part to activation of a small fraction of the implanted N near the SiO2/SiC interface as donors in SiC during oxidation, thus reducing the effects of interface trapping. In addition, the absence of oxidation-induced near-interface defects, which were observed in NO-annealed capacitors, may contribute to the improved mobility in N pre-implanted transistors.

The charge compensation in undoped GaP single crystals is investigated by modeling the Fermi level position for various concentrations of shallow and deep donors and acceptors. The model is based on the numerical solution of the charge neutrality equation and allows for calculating the Fermi energy in the temperature range of 1 –1000 K. The experimental studies of the electronic properties and concentrations of grown-in defect centers are performed by the high-resolution photoinduced transient spectroscopy (HRPITS). We show that at the shallow acceptor concentration below 1x1015 cm-3 and the concentration of deep-level defects ~3x1015 cm-3 obtaining undoped GaP with the semi-insulating (SI) properties is possible by substantial reducing the residual concentration of shallow donor impurities.

Interaction between hydrogen (H) and irradiation induced defects in p-type silicon (Si) have been studied in H implanted pn-junctions, using deep level transient spectroscopy (DLTS), as well as minority carrier transient spectroscopy (MCTS). Two H related levels at Ev+0.27 eV and Ec-0.32 eV have been observed (Ev and Ec denote the valence and conduction band edge, respectively). Both levels form after a 10 min anneal at 125C, concurrent with the release of H from the boron-hydrogen (B-H) complex. The correlated formation rates and absolute concentrations of the two levels support the notion that they are due to the same defect. In addition, a level at Ec-0.45 eV is observed and discussed in terms of vacancy-hydrogen related defects.

In the present paper, 4H-SiC JBS diodes with "boron" p–n junctions have been investigated by means of deep-level transient spectroscopy (DLTS). The sign of the DLTS signal for all the 4H-SiC diodes under study, was positive. The "anomaly" of the DLTS spectra measured is apparently connected with the properties of "boron" p–n junctions. In particular, is presented the role of deep D-centers in recompensation of donors in the JBS diodes.

To determine the energy levels of intrinsic defects in high-purity semi-insulating 4H-SiC, we apply discharge current transient spectroscopy (DCTS) that is a graphical peak analysis method based on the transient reverse current of a Schottky barrier diode, because transient capacitance methods such as deep level transient spectroscopy and isothermal capacitance transient spectroscopy are feasible only in low-resistivity semiconductors. Seven intrinsic defects are detected in the high-purity semi-insulating 4H-SiC. From the temperature dependence of the emission rate of each intrinsic defect, its activation energy is approximately determined.

Minority- and majority-carrier traps were studied in GaN pn junctions grown homoepitaxially by MOCVD on n+ GaN substrates. Two majority-carrier traps (MA1,MA2) and three minority-carrier traps (MI1, MI2, MI3) were detected by deep-level transient spectroscopy. MA1 and MA2 are electron traps commonly observed in n GaN on n+ GaN and sapphire substrates. No dislocation-related traps were observed in n GaN on n+ GaN. Among five traps in GaN pn on GaN, MI3 is the main trap with the concentration of 2.5x1015 cm-3.

The novel technique microwave detected photo induced current transient spectroscopy (MD-PICTS) was applied to semi-insulating 6H-SiC in order to investigate the properties of inherent defect levels. Defect spectra can be obtained in the similar way to conventional PICTS and DLTS. However, there is no need for contacting the samples, which allows for non-destructive and spatially resolved electrical characterization. This work is focused on the investigation of semi-insulating 6H-SiC grown under different C/Si-ratios. In the corresponding MD-PICTS spectra several shallow defect levels appear in the low temperature range. However the peak assignment needs further investigation. Additionally different trap reemission dynamics are obtained for higher temperatures, which are supposed to be due to different compensation effects.

In order to characterize traps in semi-insulating 4H-SiC that is regarded as an attractive semiconductor for X-ray detectors, we apply discharge current transient spectroscopy (DCTS) that is a graphical peak analysis method based on the transient reverse current of a diode. We have found at least three types of traps whose emission rates at 373 K are 4.9×10-3, 8.3×10-3 and 8.0×10-2 s-1. Since it is difficult to characterize traps in semi-insulating semiconductors by transient capacitance methods, it is demonstrated that DCTS is a powerful method for determining the densities and emission rates of traps in semi-insulating semiconductors.

Capacitance-voltage (C-V) and Deep-level transient spectroscopy (DLTS) measurements on AlxGa1-xN/GaN heterostructures were performed to investigate the existence of the carriers and the behavior of the deep levels in the AlxGa1-xN/GaN heterointerface. The C-V depth profile showed that the carrier concentration existed at the AlxGa1-xN/GaN heterointerface was 4 × 1012 cm2. The DLTS results showed two deep levels. The capture cross-section of the deep level related to the two-dimensional electron gas decreased with increasing depth, resulting from the existence of the different deep levels in each region.

We used electron paramagnetic resonance (EPR) and deep-level transient spectroscopy (DLTS) to quantitatively compare the concentrations of the EPR signal originally known as SI-5 and the commonly observed DLTS signal at E c -0.65 eV in bulk and epitaxial 4H- and 6H-SiC.

Deep electronic states associated with iron silicide precipitates have been studied by means of deep-level transient spectroscopy. The observed spectra show the characteristic features of bandlike states at extended defects. From the stability of the states on annealing at moderate temperature they are tentatively attributed to precipitate-matrix interfaces.

Specific on-resistance Ron estimated from current density-voltage characteristics of Schottky diodes on thick layers exhibits variations from tens of mW.cm2 to tens of W.cm2 for different doping levels. In order to understand the occurrence of high on-state resistance, Schottky barrier heights were first estimated for both forward and reverse bias with the application of thermionic emission theory and were in agreement with a literature reported values. Decrease in mobility with the temperature was observed and its dependencies of T–1.3 and T–2.0 for moderately doped and low doped samples respectively were estimated. From deep level measurements by Minority Carrier Transient Spectroscopy, an influence of shallow boron related levels and D-center on dependence of on-state resistance was observed, being more pronounced in low doped samples. Similar tendency was observed in depth profiling of Ron. This suggests a major role of boron in a compensation mechanism thus resulting in high Ron.

Conductance DLTS measurements have been performed on 4H-SiC MESFETs. A broad band due to electron emission by different levels is observed. An additional “hole-like” level with activation energy of 0.9 eV is obtained in linear regime but not in saturation regime. From the results, it is proposed that this “hole-like” signal is due to capture of electron present at a conductive SiC/SiO2 interfacial layer.

Defects in high quality 4H silicon carbide epilayers have been studied using Deep Level Transient Spectroscopy (DLTS) and Minority Carrier Transient Spectroscopy (MCTS). Both intrinsic defect related centers HS1, Z(1/2). EH6/EH7 and shallow and deep boron centers were found. Electrical properties of the boron related traps are analyzed. Comparison with the optical decay measurements shows that boron is related to the observed lateral variations of the minority carrier lifetime in low doped 4H-SiC epilayers.

Defects created by proton irradiation of n-type 4H-SiC epilayers with different fluences and six annealing steps were investigated by Deep Level Transient Spectroscopy (DLTS) and Minority Carrier Transient Spectroscopy (MCTS). Three previously unreported hole traps with energy levels of E-V + 0.35 eV, E-V + 0.44 eV, E-V + 0.80 eV and several electron traps were found. Annealing properties and dependence upon irradiation dose of majority and minority carrier traps is presented. High temperature stability of a E-V + 0.35 eV trap has been demonstrated.