Effects of Substrate Temperature on Properties of Amorphous InxGa1-xN Films Deposited by Reactive Radio Frequency Sputtering

Amorphous indium gallium nitride (a-InxGa1-xN) films were deposited at various substrate temperatures TS by simultaneous reactive rf-magnetron sputtering using GaN and InN targets. The nitrogen composition ratio increased with an increase in TS, and became almost the same as the stoichiometry ratio at a TS above 100 °C. In the X-ray diffraction patterns of the films deposited at a TS below 200 °C, no perceivable peaks assigned to crystalline InxGa1-xN were found. In those deposited at a TS above 300 °C, however, small broad peaks assigned to crystalline InxGa1-xN were observed. The dark conductivity σd increased with an increase in TS. On the other hand, the photoconductivty σp increased with an increase in TS below 200 °C and a large change in σp was not obtained at a TS above 300 °C. The photosensitivity σp/σd showed its maximum (1175) at a TS of 200 °C.