Electron injection avalanche photodiodes in short-wave infrared (SWIR) to long-wave infrared (LWIR) HgCdTe show gain and excess noise properties indicative of a single ionizing carrier gain process. The result is an electron avalanche photodiode (EAPD) with “ideal” APD characteristics including near noiseless gain. This paper reports results obtained on long-, mid-, and short-wave cutoff infrared Hg1−xCdxTe EAPDs (10 µm, 5 µm, and 2.2 µm) that use a cylindrical “p-around-n” front side illuminated n+/n-/p geometry that favors electron injection into the gain region. These devices are characterized by a uniform, exponential, gain voltage characteristic that is consistent with a hole-to-electron ionization coefficient ratio, k=αh/αe, of zero. Gains of greater than 1,000 have been measured in MWIR EAPDS without any sign of avalanche breakdown. Excess noise measurements on midwave infrared (MWIR) and SWIR EAPDs show a gain independent excess noise factor at high gains that has a limiting value less than 2. At 77 K, 4.3-µm cutoff devices show excess noise factors of close to unity out to gains of 1,000. A noise equivalent input of 7.5 photons at a 10-ns pulsed signal gain of 964 measured on an MWIR APD at 77 K provides an indication of the capability of this new device. The excess noise factor at room temperature on SWIR EAPDs, while still consistent with the k=0 operation, approaches a gain independent limiting value of just under 2 because of electron-phonon interactions expected at room temperature. The k=0 operation is explained by the band structure of the HgCdTe. Monte Carlo modeling based on the band structure and scattering models for HgCdTe predict the measured gain and excess noise behavior.
[1]
F. Ma,et al.
HgCdTe electron avalanche photodiodes
,
2004
.
[2]
Jeffrey D. Beck,et al.
MWIR HgCdTe avalanche photodiodes
,
2001,
SPIE Optics + Photonics.
[3]
Neil T. Gordon,et al.
Reverse breakdown in long wavelength lateral collection CdxHg1−xTe diodes
,
1990
.
[4]
R. Mcintyre.
Multiplication noise in uniform avalanche diodes
,
1966
.
[5]
Jeffrey D. Beck,et al.
Monte Carlo simulations of Hg0.7Cd0.3Te avalanche photodiodes and resonance phenomenon in the multiplication noise
,
2003
.
[6]
R. J. McIntyre,et al.
A new look at impact ionization-Part I: A theory of gain, noise, breakdown probability, and frequency response
,
1999
.
[7]
Maurice J. Halmos,et al.
Advances in linear and area HgCdTe APD arrays for eyesafe LADAR sensors
,
2001,
SPIE Optics + Photonics.
[8]
Michael A. Kinch.
HDVIP FPA technology at DRS Infrared Technologies
,
2001,
SPIE Defense + Commercial Sensing.
[9]
B. Orsal,et al.
Ionization energies in CdxHg1-xTe avalanche photodiodes
,
1993
.
[10]
W. Shockley.
Problems related to p-n junctions in silicon
,
1961
.