Journal of Electronic Materials

, Volume 37, Issue 9, pp 1261–1273

Impulse Response Time Measurements in Hg0.7Cd0.3Te MWIR Avalanche Photodiodes


  • Johan Rothman
  • Gerard Destefanis
  • Jean-Paul Chamonal

DOI: 10.1007/s11664-008-0459-7

Cite this article as:
Perrais, G., Rothman, J., Destefanis, G. et al. Journal of Elec Materi (2008) 37: 1261. doi:10.1007/s11664-008-0459-7


The response time of front-sided illuminated n-on-p Hg0.7Cd0.3Te electron avalanche photodiodes (e-APDs) at T = 77 K was studied using impulse response measurements at λ = 1.55 μm. We measured typical rise and fall times of 50 ps and 800 ps, respectively, at gains of M ≈ 100, and a record gain-bandwidth (GBW) product of GBW = 1.1 THz at M = 2800. Experiments as a function of the collection width have shown that the fall time is strongly limited by diffusion. Variable-gain measurements showed that the impulse response is first-order sensitive to the level of the output amplitude. Only a slight increase in the rise time and the fall time was observed with the gain at constant output amplitude, which is consistent with a strongly dominant electron multiplication. Comparisons of the experimental results with Silvaco finite element simulations confirmed the diffusion limitation of the response time and allowed the illustration of the transit time and RC effects.


HgCdTeAPDbandwidth BWimpulse response timeSilvaco simulationLPEMBE

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© TMS 2008