Abstract: Etching process of back-illuminated ZnO ultraviolet focal plane array imagers was investigated.The etching result of 128×128 array,in which the area of unit cell was 25μm×25μm,was studied.The profile angle was approximately 80°. There was a linear relationship between the etching depth and the etching time.The dependence of etching rate on NH4Cl solution concentration was also studied.The photoresponsivity of the array's unit cells was measured.The UV-to-visible rejection ratio was around 60∶1.

Key words: etching, NH4Cl, focal plane array