Sulfur Passivation of InP/InGaAs Metal‐Semiconductor‐Metal Photodetectors

In this paper, we report on the fabrication of high‐performance In0.53Ga0.47As/InP metal‐semiconductor‐metal photodetectors (MSM‐PDs) using sulfur passivation of the InP surface. Sulfur passivation resulted in a more reliable and reproducible performance, more consistency from device to device, and improved aging stability. The InGaAs MSM‐PDs (2 × 2 μm) have a dark current of about 200 ± 10 nA (at 10 V), a low capacitance of 200 ± 10 fF, a breakdown voltage of about 20 V, a fairly high responsivity of 0.75 ± 0.05 A/W, and a full width at half‐maximum of the temporal response (at λ = 1.3 μm) of 8.5 ± 0.2 ps, which corresponds to a 3 dB frequency of 20 GHz. In addition to the significantly reduced dark current, the field dependence of the photocurrent is also substantially minimized after passivation. Improvement of MSM‐PD performance by sulfur passivation is attributed to the increase of the Schottky barrier height and the reduction of surface and/or interface states. © 1999 The Electrochemical Society. All rights reserved.