Material and electronic properties of boron-doped silicon films deposited from SiH 4BCl 3N 2 mixtures in an industrial low pressure chemical vapour deposition furnace

Abstract

Heavily boron-doped polycrystalline silicon (p-Si) films were deposited in the 520–605°C temperature range using an industrial low pressure chemical vapour deposition (LPCVD) reactor equipped with gas injectors. The simulation of the film deposition rates and the theoretical calculations of the distribution of gaseous species along the reactor load showed that, in all the cases studied, the wafer position in the process load had only a small effect on the local deposition parameters for the films. From characterization by transmission electron microscopy of plane view and cross-section, reflection high energy electron diffraction patterns and Raman spectroscopy, the polycrystalline character of the boron-doped silicon films appears to result from heterogeneous crystal nucleation and growth occurring at the gas-film interface during deposition at temperatures T d≤520°C. The increase in the number of crystalline Si(c-Si) nuclei is responsible for the smaller grain size of the silicon films deposited at T d≥560°C. Correlations between deposition parameters and surface roughness, polarization properties at 405 nm and electrical resistivity of the films were established. Comparisons with the microstructure and properties of undoped and in situ phosphorus-doped LPCVD silicon films were also carried out.