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 X 2 mu m) 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 lambda = 1.3 mu m) 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.