Fabrication of Metal-Semiconductor-Metal Photodetectors Using Low Temperature Rapid Thermal Annealing

Abstract

The electrical properties of Ti-Si-Ti Metal-Semiconductor-Metal (MSM) photodetector were studied as a function of annealing temperature using the Rapid Thermal Annealing (RTA) process. Low temperatures were used at the RTA (200-350{degree sign}C) in order to avoid the formation of silicides. We observed a decrease in the dark current on samples annealed between 200 and 300{degree sign}C. The lowest dark current obtained was in the sample annealed at 250{degree sign}C (4.8 nA), which is one order of magnitude lower than as-deposited sample (53.5 nA). The sample annealed at 350 {degree sign}C had an increase in dark current (82.9 nA). This behavior of the dark current can be explained by the increase in the barrier height at 200-300 {degree sign}C annealing temperature range (due to increase of the thickness of the amorphous interdiffused Ti-Si interfacial layer) and decrease in the barrier value at sample annealed at 350{degree sign }C (due to pre formation of C49 TiSi2).