Depletion region

About: Depletion region is a research topic. Over the lifetime, 9393 publications have been published within this topic receiving 145633 citations.

Enhanced numerical analysis of current-voltage characteristics of long wavelength infrared n-on-p HgCdTe photodiodes

Abstract: An enhanced original computer program is applied to explain in detail the current-voltage characteristics of n-on-p long wavelength infrared HgCdTe photodiodes. The computer program solves the system of nonlinear continuity equations for carriers and Poisson equations. In the model ideal diode diffusion, generation-recombination, band-to-band tunneling, trap-assisted tunneling, and impact ionization are included as potential limiting mechanisms in the photodiodes. It is a clearly explained influence of Hg-vacancy doping and extrinsic doping of an active device region on dark current-voltage characteristics and an R0A product of HgCdTe photodiodes in a wide region of temperature and wavelengths. Special attention is directed to the dependence of tunneling probability on the shape of potential barrier with in an depletion region. The theoretical predictions are compared with experimental data of high quantity photodiodes published in the available literature.

Non-equilibrium C-V and I-V characteristics of metal-insulator-semiconductor capacitors

Abstract: The C-V characteristics of metal-insulator-semiconductor (MIS) structures exhibit considerable departure from their quasi-equilibrium behavior under the application of large depleting voltages. The deviation is the result of d.c. current flowing through the insulator, so that steady state non-equilibrium conditions exist in the semiconductor. The primary effects are a lowering of the high frequency capacitance below its quasi-equilibrium minimum value C ∞ , a deviation of the I-V characteristics of the structure from those of the insulator and the development of a large voltage drop across the semiconductor. The low and high frequency capacitances coincide in this non-equilibrium range. The non-equilibrium properties have been observed for deposited films of Si 3 N 4 , SiO 2 , and Al 2 O 3 . Experimental data are presented for films of pyrolytically deposited Si 3 N 4 on p - and n -type silicon substrates, in the dark and for various levels of illumination. A model is developed in which current in the semiconductor occurs through the generation of carriers in the depletion region, and bulk diffusion of carriers in the case of illumination, and where the insulator current proceeds through the Poole-Frenkel mechanism. Agreement between theory and experiment is obtained, and the possible use of the non-equilibrium effect in determining the minority carrier lifetime of the substrate is indicated.

High-voltage vertical Ga2O3 power rectifiers operational at high temperatures up to 600 K

Abstract: This work presents the temperature-dependent forward conduction and reverse blocking characteristics of a high-voltage vertical Ga2O3 power rectifier from 300 K to 600 K. Vertical β-Ga2O3 Schottky barrier diodes (SBDs) were fabricated with a bevel-field-plated edge termination, where a beveled sidewall was implemented in both the mesa and the field plate oxide. The Schottky barrier height was found to increase from 1.2 eV to 1.3 eV as the temperature increases from 300 K to 600 K, indicating the existence of barrier height inhomogeneity. The net donor concentration in the drift region shows little dependence on the temperature. The reverse leakage current up to 500 V was found to be limited by both the thermionic-field electron injection at the Schottky contact and the electron hopping via the defect states in the depletion region. At 300–500 K, the leakage is first limited by the electron injection at low voltages and then by the hopping in depleted Ga2O3 at high voltages. At temperatures above 500 K, the thermionic field emission limits the device leakage over the entire voltage range up to 500 V. Compared to the state-of-the-art SiC and GaN SBDs when blocking a similar voltage, our vertical Ga2O3 SBDs are capable of operating at significantly higher temperatures and show a smaller leakage current increase with temperature. This shows the great potential of Ga2O3 SBDs for high-temperature and high-voltage power applications.

Two‐dimensional electron gas structures with mobilities in excess of 3×106 cm2 V−1 s−1

Abstract: We have demonstrated that the mobility of two‐dimensional electron gas (2DEG) structures shows a gradual improvement with the number of uninterrupted growth runs in the molecular‐beam‐epitaxy system. Some, but not all, of this improvement can be attributed to the cleanup of the GaAs layers in the structure, and we suggest that there is a corresponding cleanup of the (Al,Ga)As which is also influencing the mobility. Once the system has passed the cleanup phase, a systematic trend of carrier density and mobility with undoped spacer thickness was observed, with a peak mobility at 4 K of 2.12×106 cm2 V−1 s−1 for a sheet carrier density of 2×10−11 cm−2 occurring at a spacer thickness of 800 A. A further increase in mobility was achieved by using a thicker region of doped (Al,Ga)As, thereby moving the ionized centers in the surface depletion layer further away from the 2DEG. This has enabled us to produce a sample with mobility at 4 K of 3.1×106 cm2 V−1 s−1 (at a sheet charge of 3.1×1011 cm−2)—the first time su...

Equilibrium Point Defect and Electronic Carrier Distributions near Interfaces in Acceptor-Doped Strontium Titanate

Abstract: A mathematical model based on Frenkel's theory for charged defect segregation at interfaces is used to calculate the equilibrium grain boundary depletion layer widths and conductivity profiles in acceptor-doped SrTiO3 ceramics. The calculations examine the effect of oxygen vacancy equilibration during annealing at moderate temperatures (∼1000 K) on the development of interfacial charge that influences grain boundary electrical properties at lower temperatures. Good agreement is demonstrated between the model predictions and experimental results reported in the literature.