Direct Nucleation and Selective Growth of Nuclei for High Crystallinity Poly-Sige Thin Films on Sio2 Substrates

Abstract

ABSTRACTWe have proposed a new technique for high crystallinity polycrystalline SiGe thin films with homogeneous crystallinity. The key technologies, i.e., direct nuclei formation on the substrate surface and selective growth of the resulting nuclei to gains, were established irrespective of film composition in a reactive thermal CVD with GeF4 and Si2H6. High crystallinity poly-Si0.05Ge0.95 thin films could be obtained on SiO2 substrates at 375°C and poly-Si0.95Ge0.05 thin films at 450°C by simply tuning the growth pressure for selective growth of the nuclei after creating the nuclei on the substrates. We demonstrated that not only the crystallinity but also the electrical properties of the resulting films were improved very much compared with those of continuously grown films.