Fabrication of Ti-Si-Ti 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 Rapid Thermal Annealing (RTA) process. Low temperatures were used at the RTA (200-350°C) in order to avoid the formation of silicides.We observed a decrease in the dark current on samples annealed between 200 and 300°C. The lowest dark current was obtained in the sample annealed at 250°C (4.8 nA), which is one order of magnitude lower than as-deposited sample (53.5 nA). The sample annealed at 350°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°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°C, due to pre formation of C49 TiSi2.