排序方式: 共有21条查询结果,搜索用时 31 毫秒
1.
Nener B.D. Lai S.T. Faraone L. Nassibian A.G. 《IEEE transactions on instrumentation and measurement》1993,42(5):913-919
A method of directly evaluating the activation energy ΔE, capture cross section σ, and density NT, of deep-level traps from the pulsed reverse bias capacitance transient is described. The main advantages of this technique are that it requires only a single temperature scan, and it can resolve nonexponential transients due to closely-spaced energy levels. The test samples used for this paper consisted of Schottky diodes fabricated on nonirradiated and 1-MeV electron-irradiated n-type VPE (vapor-phase epitaxy) GaAs wafers. The well known EL2 trap was identified with ΔE of 0.81 eV, and σ n of 1.0×10-13 cm2 for the nonirradiated sample. These values were found to be in good agreement with published data using established, conventional DLTS techniques. For the irradiated samples a nonexponential capacitance transient was found in the EL2 range of temperatures. The discussed technique was able to resolve two closely spaced deep levels lying at Ec-0.81 eV and Ec-0.84 eV, and with capture cross sections of 1.5×10-13 cm2 and 2.5×10-12 cm2, respectively 相似文献
2.
It is postulated that donor-like nitrogen vacancies, caused by the sputtering of a Schottky-barrier metal onto p-type gallium nitride, diffuse into the GaN and form a surface layer in which both the minority-carrier lifetime and mobility are drastically reduced. Such a damaged surface layer is shown to reduce the responsivity of p-GaN Schottky-barrier photodiodes, thereby offering an explanation for the responsivity values in the range of 0.03–0.04 A/W that have been measured in experimental ITO/p-GaN devices. On making allowance for the damaged surface layer, an electron diffusion length of around 300 nm can be inferred for the undamaged p-GaN region. 相似文献
3.
Musca C.A. Siliquini J.F. Nener B.D. Faraone L. 《Electron Devices, IEEE Transactions on》1997,44(2):239-249
The theoretical and experimental performance of Hg1-xCd xTe long wavelength infrared (LWIR) photoconductors fabricated on two-layer heterostructures grown by in situ MOCVD has been studied. It is shown that heterojunction blocking contact (HBC) photoconductors, consisting of wider bandgap Hg1-xCdx Te on an LWIR absorbing layer, give improved responsivity, particularly at higher applied bias, when compared with two-layer photoconductors incorporating n+/n contacts. An extension to existing device models is presented, which takes into account the recombination rate at the heterointerface and separates it from that occurring at both the contact-metal/semiconductor and passivant/semiconductor interfaces. The model requires a numerical solution to the continuity equation, and allows the device responsivity to be calculated as a function of applied electric field. Model predictions indicate that a change in bandgap across the heterointerface corresponding to a compositional change of Δx⩾0.04 essentially eliminates the onset of responsivity saturation due to minority carrier sweepout at high applied bias. Experimental results are presented for frontside-illuminated n-type Hg1-xCdxTe photoconductive detectors with either n+/n contacts or heterojunction blocking contacts. The devices are fabricated on a two-layer in situ grown MOCVD Hg1-xCdxTe wafer with a capping layer of x=0.31 and an LWIR absorbing layer of x=0.22. The experimental data clearly demonstrates the difficulty of forming n +/n blocking contacts on LWIR material, and indicates that heterojunctions are the only viable technology for forming effective blocking contacts to narrow bandgap semiconductors 相似文献
4.
Parish G. Musca C.A. Siliquini J.F. Antoszewki J. Dell J.M. Nener B.D. Faraone L. Gouws G.J. 《Electron Device Letters, IEEE》1997,18(7):352-354
A monolithic HgCdTe photoconductive device structure is presented that is suitable for dual-band optically registered infrared photodetection in the two atmospheric transmission windows of 3-5 μm and 8-12 μm, which correspond to the mid-wave and long-wave infrared bands; MWIR and LWIR, respectively. The proposed structure employs a wider bandgap isolating layer between the two photosensitive layers such that an effective electrical barrier is formed thus prohibiting carrier transport between the two infrared absorbing layers of different cutoff wavelengths. The technology is demonstrated using a mature HgCdTe photoconductive device fabrication process. The resulting detectors have an MWIR cutoff of 5.0 μm, and LWIR cutoff of 10.5 μm 相似文献
5.
M. Kocan G.A. Umana-Membreno J.S. Chung F. Recht L. McCarthy S. Keller U.K. Mishra G. Parish B.D. Nener 《Journal of Electronic Materials》2007,36(9):1156-1159
This paper reports results of a study of non-alloyed ohmic contacts on Si-implanted AlGaN/GaN heterostructures, obtained from
current–voltage characteristics of transfer-length method (TLM) test structures. It is shown that the measured contact resistance
from the Ti/Au/Ni metal contacts, deposited on Si-implanted regions, to the two-dimensional electron gas channel at the AlGaN/GaN
heterointerface of the non-implanted region, is formed by three different components: (i) contact resistance between the metal␣and
the semiconductor (0.60 ± 0.16 Ω mm), (ii) resistance of the implanted region (0.62 ± 0.03 Ω mm) and (iii) an additional resistance
(0.72 ± 0.24 Ω mm) giving a total value of 1.9 ± 0.3 Ω mm. The specific ohmic contact resistance was determined to be (2.4 ± 0.5) × 10−5 Ω cm2. 相似文献
6.
Temperature-Dependent Characterization of AlGaN/GaN HEMTs: Thermal and Source/Drain Resistances 总被引:1,自引:0,他引:1
Menozzi R. Umana-Membreno G.A. Nener B.D. Parish G. Sozzi G. Faraone L. Mishra U.K. 《Device and Materials Reliability, IEEE Transactions on》2008,8(2):255-264
This paper shows the application of simple dc techniques to the temperature-dependent characterization of AlGaN/ GaN HEMTs in terms of the following: 1) thermal resistance and 2) ohmic series resistance (at low drain bias). Despite their simplicity, these measurement techniques are shown to give valuable information about the device behavior over a wide range of ambient/channel temperatures. The experimental results are validated by comparison with independent measurements and numerical simulations. 相似文献
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8.
M. Kocan G.A. Umana-Membreno M.R. Kilburn I.R. Fletcher F. Recht L. McCarthy U.K. Mishra B.D. Nener G. Parish 《Journal of Electronic Materials》2008,37(5):554-557
This paper reports results of scanning ion probe studies of silicon implantation profiles in source and drain regions of AlGaN/GaN
high-electron-mobility transistor (HEMT) heterostructures. It is shown that both the undoped channel length and the transition
region between implanted and non- implanted regions become wider with increasing depth in the structure. These results may
explain the previously reported existence of resistance associated with the transition region between implanted and non-implanted
semiconductor regions in AlGaN/GaN HEMT heterostructures with non-alloyed Si-implanted source and drain ohmic contact regions. 相似文献
9.
Applied Intelligence - The dynamic analysis of cell behavior is fundamental to the evaluation of the correlation between disease and abnormal cell migration. In this study, a self-regulated... 相似文献
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