Hemispherical-grained LPCVD-polysilicon films for use in MEMS applications

摘要

Hemispherical-grained (HSG) polysilicon was shown to have tensile stress built in an as-deposited layer and considerable surface roughness. These features are very different from those of conventional polysilicon and amorphous silicon, while HSG can be fabricated in a manner similar to conventional LPCVD. This is related to the fact that the formation of HSG occurs on the amorphous surface, while polycrystallization due to annealing usually occurs at the silicon-to-silicon-dioxide interface. These intrinsic characteristics of HSG are applicable to Micro Electro Mechanical Systems (MEMS) for fabricating a wide variety of freestanding structures by preventing these flexible structures from being stuck to other more rigid structures. (C) 2000 Elsevier Science S.A. All rights reserved. [References: 12]