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Title: Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes

Abstract

This work investigates the effect of surface fields on the dynamic resistance of a planar HgCdTe mid-wavelength infrared photodiode from both theoretical and experimental aspects, considering a gated n-on-p diode with the surface potential of its p-region modulated. Theoretical models of the surface leakage current are developed, where the surface tunnelling current in the case of accumulation is expressed by modifying the formulation of bulk tunnelling currents, and the surface channel current for strong inversion is simulated with a transmission line method. Experimental data from the fabricated devices show a flat-band voltage of V{sub FB}=−5.7 V by capacitance-voltage measurement, and then the physical parameters for bulk properties are determined from the resistance-voltage characteristics of the diode working at a flat-band gate voltage. With proper values of the modeling parameters such as surface trap density and channel electron mobility, the theoretical R{sub 0}A product and corresponding dark current calculated from the proposed model as functions of the gate voltage V{sub g} demonstrate good consistency with the measured values. The R{sub 0}A product remarkably degenerates when V{sub g} is far below or above V{sub FB} because of the surface tunnelling current or channel current, respectively; and it attains the maximum value of 5.7×10{supmore » 7} Ω · cm{sup 2} around the transition between surface depletion and weak inversion when V{sub g}≈−4 V, which might result from reduced generation-recombination current.« less

Authors:
; ; ;  [1];  [2]; ; ; ; ; ;  [1];  [3]
  1. Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)
  2. (China)
  3. Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
Publication Date:
OSTI Identifier:
22410250
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CADMIUM TELLURIDES; CAPACITANCE; ELECTRIC CONDUCTIVITY; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; ELECTRON MOBILITY; LEAKAGE CURRENT; MERCURY COMPOUNDS; PHOTODIODES; RECOMBINATION; SURFACE POTENTIAL; SURFACES; TRAPS; TUNNEL EFFECT

Citation Formats

He, Kai, Wang, Xi, Zhang, Peng, Chen, Yi-Yu, University of Chinese Academy of Sciences, Beijing 100049, Zhou, Song-Min, Xie, Xiao-Hui, Lin, Chun, E-mail: chun-lin@mail.sitp.ac.cn, Ye, Zhen-Hua, Wang, Jian-Xin, Zhang, Qin-Yao, E-mail: qinyao@mail.sitp.ac.cn, and Li, Yang. Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes. United States: N. p., 2015. Web. doi:10.1063/1.4921593.
He, Kai, Wang, Xi, Zhang, Peng, Chen, Yi-Yu, University of Chinese Academy of Sciences, Beijing 100049, Zhou, Song-Min, Xie, Xiao-Hui, Lin, Chun, E-mail: chun-lin@mail.sitp.ac.cn, Ye, Zhen-Hua, Wang, Jian-Xin, Zhang, Qin-Yao, E-mail: qinyao@mail.sitp.ac.cn, & Li, Yang. Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes. United States. doi:10.1063/1.4921593.
He, Kai, Wang, Xi, Zhang, Peng, Chen, Yi-Yu, University of Chinese Academy of Sciences, Beijing 100049, Zhou, Song-Min, Xie, Xiao-Hui, Lin, Chun, E-mail: chun-lin@mail.sitp.ac.cn, Ye, Zhen-Hua, Wang, Jian-Xin, Zhang, Qin-Yao, E-mail: qinyao@mail.sitp.ac.cn, and Li, Yang. Thu . "Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes". United States. doi:10.1063/1.4921593.
@article{osti_22410250,
title = {Effect of surface fields on the dynamic resistance of planar HgCdTe mid-wavelength infrared photodiodes},
author = {He, Kai and Wang, Xi and Zhang, Peng and Chen, Yi-Yu and University of Chinese Academy of Sciences, Beijing 100049 and Zhou, Song-Min and Xie, Xiao-Hui and Lin, Chun, E-mail: chun-lin@mail.sitp.ac.cn and Ye, Zhen-Hua and Wang, Jian-Xin and Zhang, Qin-Yao, E-mail: qinyao@mail.sitp.ac.cn and Li, Yang},
abstractNote = {This work investigates the effect of surface fields on the dynamic resistance of a planar HgCdTe mid-wavelength infrared photodiode from both theoretical and experimental aspects, considering a gated n-on-p diode with the surface potential of its p-region modulated. Theoretical models of the surface leakage current are developed, where the surface tunnelling current in the case of accumulation is expressed by modifying the formulation of bulk tunnelling currents, and the surface channel current for strong inversion is simulated with a transmission line method. Experimental data from the fabricated devices show a flat-band voltage of V{sub FB}=−5.7 V by capacitance-voltage measurement, and then the physical parameters for bulk properties are determined from the resistance-voltage characteristics of the diode working at a flat-band gate voltage. With proper values of the modeling parameters such as surface trap density and channel electron mobility, the theoretical R{sub 0}A product and corresponding dark current calculated from the proposed model as functions of the gate voltage V{sub g} demonstrate good consistency with the measured values. The R{sub 0}A product remarkably degenerates when V{sub g} is far below or above V{sub FB} because of the surface tunnelling current or channel current, respectively; and it attains the maximum value of 5.7×10{sup 7} Ω · cm{sup 2} around the transition between surface depletion and weak inversion when V{sub g}≈−4 V, which might result from reduced generation-recombination current.},
doi = {10.1063/1.4921593},
journal = {Journal of Applied Physics},
number = 20,
volume = 117,
place = {United States},
year = {Thu May 28 00:00:00 EDT 2015},
month = {Thu May 28 00:00:00 EDT 2015}
}
  • Investigations of the performance of GaAs/AlGaAs quantum well IR photoconductors (QWIPs) as compared to HgCdTe photodiodes operated at temperatures below 77 K in the long-wavelength IR (LWIR) region are presented. In comparative studies, the current standard n[sup +]-p HgCdTe photodiodes as well as p[sup +]-n photodiodes are considered. Investigations of the fundamental physical limitations of HgCdTe photodiodes indicate better performance of this type of detector in comparison with QWIPs operated in the range 40 to 77 K. At 40 K, QWIPs with a cutoff wavelength of about 8 [mu]m indicate higher detectivity. The advantage of QWIPs increases in wider spectralmore » regions and at temperatures below 40 K. Usually, in the temperature range below 50 K the performance of n[sup +]-p HgCdTe photodiodes is determined by trap-assisted tunneling. As a result, the advantage of GaAs/AlGaAs QWIPs increases in wider spectral regions ([lambda][sub c] [approx]8 to 12 [mu]m) and at temperatures below 50 K. The comparison with p[sup +]-n HgCdTe photodiodes is more complicated for lack of precisely modeled current transport in these junctions. GaAs/AlGaAs QWIPs at 40 K are background limited in low-background conditions. This observation plus the maturity of GaAs/AlGaAs technology and its radiation hardness characteristics promise that QWIP technology can produce high-quality focal plane arrays for space applications.« less
  • The performance of thermoelectrically cooled p[sup +]-n medium-wavelength infrared (MWIR) HgCdTe photodiodes is analyzed. The effect of doping profile on the photodiode parameters (R[sub 0]A product, quantum efficiency) is solved by forward-condition steady-state analysis. Results of calculations are compared with experimental data. The p[sup +]-n homojunctions are formed by arsenic diffusion in HgCdTe epilayers. MWIR photodiodes effectively operate at elevated temperatures around 200 K and exhibit background-limited photodetection (BLIP) performance when monolithic optical immersion is used.
  • In this paper, we report on the disappearance of the photosensitive area extension effect and the unusual temperature dependence of junction transformation for mid-wavelength, n-on-p HgCdTe photovoltaic infrared detector arrays. The n-type region is formed by B{sup +} ion implantation on Hg-vacancy-doped p-type HgCdTe. Junction transformations under different temperatures are visually captured by a laser beam induced current microscope. A physical model of temperature dependence on junction transformation is proposed and demonstrated by using numerical simulations. It is shown that Hg-interstitial diffusion and temperature activated defects jointly lead to the p-n junction transformation dependence on temperature, and the weaker mixedmore » conduction compared with long-wavelength HgCdTe photodiode contributes to the disappearance of the photosensitive area extension effect in mid-wavelength HgCdTe infrared detector arrays.« less
  • HgCdTe is a suitable material for infrared (IR) detector applications in the two atmospheric spectra`s window, (i.e., 3--5 {micro}m and 8--12 {micro}m). Unlike other IR materials such as InSb, one can easily change the composition ratio between Hg and Cd to adjust the bandgap energy of HgCdTe and thus to adjust the corresponding wavelength. Also, because of its intrinsic property, HgCdTe photo detector has a long carrier life time and a small thermal generation rate that is important for high temperature operation. A new surface treatment method, i.e., stacked ZnS/photo-enhanced native oxide, is proposed for HgCdTe passivation. The photo nativemore » oxide layer was deposited by direct photo chemical vapor deposition (DPCVD) using a deuterium (D{sub 2}) lamp as the optical source. By using this method, they found that there is no accumulation of Hg in the oxide/HgCdTe interface regions. Since the photo chemical vapor native oxidation is a dry oxidation method deposited at a low temperature, it can effectively suppress the Hg enhancement and the Cd depletion effects and thus obtain a high quality interface. The electrical properties of a Au-ZnS/photo-enhanced native oxide/HgCdTe metal-insulator-semiconductor (MIS) diodes were characterized by capacitance-voltage (C-V) measurement. It was found that the flat band voltage of such a MIS diode is close to 0.2 V with an effective fixed oxide charge lower than 1 {times} 10{sup 10} cm{sup {minus}2}.« less
  • We have performed the study on the dependence of laser beam induced current (LBIC) spectra on the temperature for the vacancy-doped molecular beam epitaxy grown Hg{sub 1−x}Cd{sub x}Te (x = 0.31) photodiodes by both experiment and numerical simulations. It is found that the measured LBIC signal has different distributions for different temperature extents. The LBIC profile tends to be more asymmetric with increasing temperature below 170 K. But the LBIC profile becomes more symmetric with increasing temperature above 170 K. Based on a localized leakage model, it is indicated that the localized junction leakage can lead to asymmetric LBIC signal, in good agreement withmore » the experimental data. The reason is that the trap-assisted tunneling current is the dominant leakage current at the cryogenic temperature below 170 K while the diffusion current component becomes dominant above the temperature of 170 K. The results are helpful for us to better clarify the mechanism of the dependence of LBIC spectra on temperature for the applications of HgCdTe infrared photodiodes.« less