Abstract
Gallium nitride powder is employed as a target material for sputtering deposition. A powder target offers the merit of easy formation of an n-type or p-type semiconductor film. In this study, the effect of the powder target is investigated. Crystal orientation and residual stress in GaN films deposited by radio frequency (RF) sputtering with the powder target are investigated by X-ray diffraction (XRD) as functions of nitrogen concentration (C N2 ) in the atmosphere gas consisting of argon and nitrogen. In addition, the film surfaces are observed by atomic force microscopy (AFM). The following results are obtained: (1) GaN films deposited by sputtering with the powder target attained good crystal orientation, with the c-axis oriented normal to the substrate surface; (2) film thickness decreased with increasing nitrogen concentration (C_<N2>); (3) the film deposited at C_<N2>=20% had the largest crystal grain size, and the film deposited at C_<N2>=0% had the smallest; (4) the film deposited at C_<N2>=20% had the smallest degree of c-axis orientation, and that deposited at C_<N2>=0% had the largest; (5) tensile residual stress occurred in films deposited at C_<N2>≦20%, and compressive residual stress over -1 GPa occurred in films deposited at C_<N2>≧50%.
