Improving the Transient Response of a Si Metal-Semiconductor-Metal Photodetector with an Additional i-a-SiGe:H Film

Abstract

An annealed intrinsic hydrogenated amorphous silicon germanium (i-a-SiGe:H) barrier layer deposited on a Si wafer ([111], 4 k Ω-cm) was employed to fabricate a planar interdigitated metal-semiconductor-metal photodetector (MSM-PD). At a bias of 15 V, and an incident light wavelength of 850 nm, this Si-based MSM-PD with an annealed 70 nm i-a-SiGe:H film had a responsivity of about 0.32 A/W, and a dark current density of around 400 fA/µ m2. Also, the temporal response of this device had a rise time of 21 ps, a fall-time of 236 ps and a full-width at half-maximum (FWHM) of 51 ps.

Modification and Modeling of Ni/Si Interface for Photodetector Applications

“…In this region, silicon is a much cheaper choice of base material, as a compared to Ill-V compounds such as GaAs or InP, and the capability of process integration with the well-developed Si integrated-circuit (IC) technology as compared with the ones made with compound semiconductors [1][2][3][4][5][6][7][8][9][10][11]. The disadvantage of silicon is its long absorption length ( 12.7 ptm) in the visible region, which results in photodetector with a severe trade-off between responsivity and bandwidth.…”

“…To solve these problems, many researchers and authors have concentrated to improve the performance of Si based MSM photodetector. Several methods such as ion-implanting the absorbing layer [4], reducing the spacing between the interdigitated electrodes [5], fabricating with an additional amorphous Si alloy and amorphous SiGe film [6][7][8][9] were suggested. In contrast, relatively little work has been reported on the effect of surface and temperature treatment on the current response in Si based MSM photodetector.…”