Thermal stability and crystallization products of amorphous Si:P alloy thin films made by coevaporation of Si and P

Thermal stability and crystallization of amorphous Si:P alloy thin films consisting of 20–44 at. % P have been studied in this work. The results show that the alloys have crystallization temperatures ranging from 850 to 1150 °C, which are all higher than that of pure amorphous Si, and that the variation of resistivity of the alloys during the 120 h aging at 300 °C is small (0.6%). These results indicate that the alloys have a high thermal stability, which is in agreement with the thermodynamic prediction we have made. It has also been observed that the crystallization products for these alloys are different. A new silicon phosphide phase has been observed in the 30 at. % alloy sample and suggested to be possibly a hexagonal Si7P3 phase which has lattice parameters a=5.32 A and c=13.3 A. The alloy films were deposited onto quartz substrates and Si wafers by coevaporation of Si and P. X‐ray diffractometry and transmission electron microscopy were utilized to investigate the crystallization temperature and p...