A. Sellai et P. Dawson, MONTE-CARLO CALCULATIONS OF QUANTUM YIELD IN INHOMOGENEOUS PTSI P-SI SCHOTTKY BARRIERS/, Semiconductor science and technology, 13(7), 1998, pp. 700-704
Monte Carlo calculations of quantum yield in PtSi/p-Si infrared detect
ors are carried out taking into account the presence of a spatially di
stributed barrier potential. In the 1-4 mu m wavelength range it is fo
und that the spatial inhomogeneity of the barrier has no significant e
ffect on the overall device photoresponse. However, above lambda = 4.0
mu m and particularly as the cut-off wavelength (lambda approximate t
o 5.5 mu m) is approached, these calculations reveal a difference betw
een the homogeneous and inhomogeneous barrier photoresponse which beco
mes increasingly significant and exceeds 50% at lambda = 5.3 mu m. It
is, in fact, the inhomogeneous barrier which displays an increased pho
toyield, a feature that is confirmed by approximate analytical calcula
tions assuming a symmetric Gaussian spatial distribution of the barrie
r. Furthermore, the importance of the silicide layer thickness in opti
mizing device efficiency is underlined as a trade-off between maximizi
ng light absorption in the silicide layer and optimizing the internal
yield. The results presented here address important features which det
ermine the photoyield of PtSi/Si Schottky diodes at energies below the
Si absorption edge and just above the Schottky barrier height in part
icular.