Characteristics of Photodiode Using a Schottky Barrier

摘要

The proposed photodiode is obtained a sufficient photo/dark current ratio by a schottky barrier. We have fabricated an aluminum film formed as a lower electrode over the glass substrate, an alumina film formed as a schottky barrier over the aluminum film, a hydrogenated amorphous silicon film formed as a photo conduction layer over a portion of the alumina film, and a transparent conduction film formed as an upper electrode over the hydro-generated amorphous silicon film. A good quality of alumina (Al_2O_3) film is formed by oxidation of aluminum film using electrolyte solution of succinic acid. It controls a restriction of dark current. In case of photodiode made by changing a formation condition of alumina, we can obtain a stable dark current (～10~(-12)A) in alumina thickness below 1000A. At the reverse bias state of "-" voltage in ITO, the photo current has a substantially constant value of 5x10~(-9)A at light scan of 1001x.