4H-SiC Schottky Array Photodiodes for UV Imaging Application Based on the Pinch-off Surface Effect
The fabrication of high sensitive diodes array is very attractive for spectroscopic and astronomical UV imaging applications, particularly when visible light rejection is required. Wide band gap materials are excellent candidates for UV “visible blind” detection. In this paper, we demonstrate an array of Schottky UV-diodes on 4H-SiC with a single pixel area of about 1.44 mm2 and a total area of about 29 mm2. The Schottky photodiodes are based on the pinch-off surface effect, the front electrode being an interdigit Ni2Si contact that allows the direct light exposure of the optically active device area. For the proposed array, the optically active area is about the 48 % of total area. The single pixel dark current was below 0.1 nA up to –50 V and a fabrication yield of about 90 % was observed. The external quantum efficiency of the proposed array exhibits a peak of 45 % at the 289 nm wavelength and a visible rejection ratio > 4 ×103.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
A. Sciuto et al., "4H-SiC Schottky Array Photodiodes for UV Imaging Application Based on the Pinch-off Surface Effect", Materials Science Forum, Vols. 556-557, pp. 945-948, 2007