Effect of film thickness on electrical property of microcrystalline silicon

We report dependences of electrical properties on SiH4/H2 dilution rate and film thickness for microcrystalline silicon films formed by a hydrogen radical-induced chemical vapor deposition (HRCVD) method. The electrical conductivity of the films at SiH4 18 sccm /H2 120 sccm was markedly increased to 10−3 S/cm as film thickness increased above 100 nm. Crystalline grains with (2 2 0) orientation were formed. Theoretical analysis revealed that grain boundaries among (2 2 0) grains had a low defect density of 1×1012 cm−2 so that the high conductivity was achieved.