Growth of poly–Si thin films on SiO₂ substrates with Ge islands

Abstract

High–quality polycrystalline Si films on insulating substrates are expected to realize high–performance thin–film transistors(TFTs) and solar cells. In this study, we proposed a new process to control size and density of Ge nucleous for formation of polycrystalline Si thin films on glass or SiO₂ substrates. We investigated advantageous effect of crystalline Ge islands for growth of poly–Si and found that the Ge nucleous enhanced poly–Si formation on SiO₂. We employed electro beam evaporation and plasma chemical vapor deposition as a–Si deposition processes. It is found that a–Si:H is superior to a–Si for solid phase crystallization. We have demonstrated that this process has a great advantage in crystallization temperature and time for obtaining large–grained poly–Si films.