Effects of Dead Space on Avalanche Gain Distribution of X-Ray Avalanche Photodiodes

Gomes, Rajiv B.; Tan, Chee Hing; Lees, J.E.; David, J.P.R.; Ng, Jo Shien

doi:10.1109/ted.2012.2182674

Cited by 13 publications

(19 citation statements)

References 20 publications

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“…The model is then applied to template staircase APDs in Sec.IV to demonstrate that it is consistent with the theory in [12]. Comparison with experimental literature data for heterojunction [4], [5] and staircase APDs [2] is provided in Sec.V. Conclusions are finally drawn in Sec.VI.…”

Section: Introductionsupporting

confidence: 72%

An Improved Nonlocal History-Dependent Model for Gain and Noise in Avalanche Photodiodes Based on Energy Balance Equation

Pilotto

Palestri

Selmi

et al. 2018

IEEE Trans. Electron Devices

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We present a non-local history-dependent model for impact ionization gain and noise in avalanche photodiodes (APDs) especially suited for staircase APDs. The model uses a simple energy balance equation to define effective electric fields valid also in the presence of band discontinuities which are then used to express the ionization coefficients. The model parameters have been calibrated against literature data for gain and noise in GaAs and AlxGa1−xAs (x = 0.2, 0.6, 0.8) p-in diodes. Application to experimental data for gain and noise in heterojunction and staircase SAM-APDs is reported to demonstrate the ability of the model in describing complex APD structures. It is found that, in spite of conduction band discontinuities being much larger than valence band ones, hole impact ionization contributes a significant degradation of the noise metrics in GaAs/AlGaAs staircase APDs. These non-trivial insights demonstrate the usefulness of the model to steer device design and optimization.

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Section: Introductionsupporting

confidence: 72%

An Improved Nonlocal History-Dependent Model for Gain and Noise in Avalanche Photodiodes Based on Energy Balance Equation

Pilotto

Palestri

Selmi

et al. 2018

IEEE Trans. Electron Devices

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“…The temperature dependence is reported over the range of 261 K-342 K and is found to be best represented by the equation e AlGaAs ¼ 7.327-0.0077 T, where e AlGaAs is the average electron-hole pair creation energy in eV and T is the temperature in K. The compound semiconductor Al 0.8 Ga 0.2 As has received attention as a detector material for use in soft X-ray spectroscopy instruments which need to operate at high temperature ()20 C). [1][2][3][4][5][6][7][8][9][10][11][12][13] At high temperatures, the wide bandgap of Al 0.8 Ga 0.2 As (2.09 eV (Ref. 14)) leads to a thermally generated leakage current lower than that which would be present in a silicon detector of the same design.…”

mentioning

confidence: 99%

Temperature dependence of the average electron-hole pair creation energy in Al0.8Ga0.2As

Barnett

Lees

Bassford

2013

Applied Physics Letters

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The temperature dependence of the average energy consumed in the creation of an electron-hole pair in the wide bandgap compound semiconductor Al0.8Ga0.2As is reported following X-ray measurements made using an Al0.8Ga0.2As photodiode diode coupled to a low-noise charge-sensitive preamplifier operating in spectroscopic photon counting mode. The temperature dependence is reported over the range of 261 K–342 K and is found to be best represented by the equation εAlGaAs = 7.327–0.0077 T, where εAlGaAs is the average electron-hole pair creation energy in eV and T is the temperature in K.

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“…AlxG3.x_1As has received attention as a potentially desirable material from which to fabricate soft X -ray spectroscopic photon counting photodiodes [1][2][3][4][5][6][7][8][9]. In particular, Alo.sGao.2As X-ray photon counting spectroscopic p+-i-n+ photodiodes have been shown to operate in avalanche mode over a wide temperature range (-30 to +90°C) [4][5][6][7][8].…”

Section: In1roductionmentioning

confidence: 99%

Development of AlGaAs avalanche diodes for soft X-ray photon counting

Lees

Barnett

Bassford

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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We report on the performance of avalanche photodiodes (APDs) based on the wide band gap material AIGaAs which have been developed for soft X-ray spectroscopy applications. A number of diode types with different layer thicknesses have been characterised. The temperature dependence of the avalanche multiplication process at soft X-ray energies in Alo.sGao.zAs APDs was investigated at temperatures from +80 °C to -20°C. X-ray spectra from a 55 Fe radioactive source show these diodes can be used for spectroscopy with promising energy resolution (0.9-2.5keV) over a wide temperature range. The temperature dependence of the pure electron initiated multiplication factor (Me) and the mixed carrier initiated avalanche multiplication factor (MmO> were experimentally measured. The experimental results are compared with a spectroscopic Monte Carlo model for Alo.sGao.zAs diodes from which the temperature dependence of the pure hole initiated multiplication factor (Mh) is determined.AlxG3.x_1As has received attention as a potentially desirable material from which to fabricate soft X -ray spectroscopic photon counting photodiodes [1-9]. In particular, Alo.sGao.2As X-ray photon counting spectroscopic p+-i-n+ photodiodes have been shown to operate in avalanche mode over a wide temperature range (-30 to +90°C) [4][5][6][7][8]. For Alo.2Gao.sAs [4], Alo.4Gao. 6 As [4] and Alo.sGao.2As [5], the electric field dependence of the electron and hole impact ionization coefficients have been reported. However, the temperature dependence of the impact ionization coefficients has not receive the same amount of attention with a limited number of reports appearing in the literature for Alo.2Gao.sAs and Alo.4Gao. 6 As [4] and more recently Alo.sGao.2As [6].In this paper we show that the ionization coefficients can be extracted from measurement of the X -ray spectra as a function of bias voltage. We also report the temperature dependence of the avalanche multiplication process at a typical operating electric field in Alo.sGao.2As p+-p--n+ spectroscopic X-ray photon counting APDs. The temperature dependence of the electron and hole ionization coefficients is derived and shown. II. DIODE DESIGN AND CHARACTERISTICSThe wafer used in this study is an Alo.sGao.2As p+-p--n+ diode grown on an n+ (100) on-axis GaAs substrate (thickness of 350 flm) by a VG V80 Molecular Beam Epitaxy (MBE) machine. The fabricated diodes were unpassivated mesa APDs with radii of 25 flm, 50 /lm, 100 /lm and 200 /lm. Further details of the diode fabrication and wafer growth can be found in [4]. The major epitaxial layer material thicknesses and deduced doping densities are given in Table 1. Although the wafer was originally intended to be an Alo.sGao.2As p+-i-n+ diode, doping information deduced from devices fabricated from the wafer indicate that that the structure resembles a p + P --n + diode. TABLE I. DIODE LAYER PARAMETERS Layer Material Thickness (J.Lm) Type Na 1 AlGaAs 0.92 P 4xlO " 2 AlGaAs 0.58 P 5xlO l6 2 AlGaAs 1.0 N 2xlO I8 III. EXPERIMENTAL METHODThe diodes were co...

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Effects of Dead Space on Avalanche Gain Distribution of X-Ray Avalanche Photodiodes

Cited by 13 publications

References 20 publications

An Improved Nonlocal History-Dependent Model for Gain and Noise in Avalanche Photodiodes Based on Energy Balance Equation

An Improved Nonlocal History-Dependent Model for Gain and Noise in Avalanche Photodiodes Based on Energy Balance Equation

Temperature dependence of the average electron-hole pair creation energy in Al0.8Ga0.2As

Development of AlGaAs avalanche diodes for soft X-ray photon counting

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