Control of the azimuthal orientation of grains in polycrystalline Si films

Multi-directional ion beam irradiation is applied to control the crystal orientation of Si thin films during growth via plasma-enhanced chemical vapor deposition. The primary ion beam is generated by electron cyclotron resonance using an SiH4/H2 mixture, and the auxiliary beam is obtained by redirecting a portion of the primary beam with a metal reflector. These two beams simultaneously hit the surface of the growing film from different directions. With this arrangement, we succeeded in controlling the orientation of the growth of deposited Si grains in virtually the same direction.