A Novel Method to Make Boron-Doped Microcrystalline Silicon Thin Films with Optimal Crystalline Volume Fraction for Thin Films Solar Cell Applications

摘要

Highly conducting boron-doped microcrystalline silicon (p-type μc-Si:H) thin films have been prepared by radio frequency plasma-enhanced chemical-vapor deposition (RF-PECVD). In this work, the effects of hydrogen dilution, doping ratio, plasma power, deposition pressure and substrate temperature on the growth and the properties of boron-doped microcrystalline silicon (p-type μc-Si:H) thin films are investigated. The electrical, chemical and structural properties are improved with increasing crystallite, which depends on the plasma conditions. For various plasma parameters, the crystalline volume fraction (X_c), dark conductivity (σ_d), activation energy (E_a), hydrogen content (C(H)), surface roughness (S_r), and micro void fraction (R~*) were measured, and they were 0～72%, 4.17～10~(-4) S/cm～1.1 S/cm, 0.041～0.113 eV, 3.8～11.5 at.%, 3.2 nm～12.2 nm, and 0.47～0.80, respectively. The film with R~* of 0.47 and C(H) of about 5 at.% belonged to a region of low disorder, and acted as a good passivation layer.