Grain Growth and Conductive Characteristics of Super Thin Polysilicon Films by Oxidation

Abstract

Improved characteristics of electronic conduction and grain growth effect of super thin CVD polysilicon films after thermal oxidation (less than 1000 Å thick) were investigated. After oxidation of CVD silicon, grain size grew two-dimensionally to as large as 1500 Å in diameter with a thickness of 300 Å. In contrast, temperature dependence of conductivity changed from T ^-(1/4) rule to T ^-1 rule after oxidation. The grain growth effect after oxidation to super thin films (200–300 Å thick) was found to affect the decrease in grain boundary barrier height, which resulted in the increase of carrier mobility.