Hydrogenated amorphous silicon position sensitive detector

The design, fabrication, and characterization of newly developed hydrogenated amorphous silicon position sensitive detectors (a-Si:H PSDs) which employ a tunnel metal-insulator-semiconductor (MIS) structure fabricated by anodic oxidation processes are described. Tunnel MIS structure is chosen as the a-Si:H PSD structure, since it offers high breakdown voltage compared to a-Si:H pin or Schottky-type structures. PSD process includes two-step anodic oxidation of a-Si:H: (1) oxidation in the dark to passivate defects and shunt paths introduced during the growth of a-Si:H layer and (2) oxidation with light to grow thin native oxide to provide barrier between metal and a-Si:H. The fabricated large-area, two-dimensional PSDs, as large as 3 cm×3 cm, show the incident beam position within error of less than 2% of the length of PSD.