The Electrical Properties of In-situ Doped Polycrystalline Silicon Thin Films Grown by Electron Cyclotron Resonance Chemical Vapor Deposition at 250°C

The phosphorus doped polycrystalline silicon thin films were grown by Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) at 250°C. The doping gas PH3 was in-situ added with SiH4 gas during the films deposition. All films were deposited with 90% hydrogen dilution ratio. The resistivity of the films is varied from 0.2 to 7Ω-cm and decrease as the PH3/SiH4 gas ratio increase from (3/100 to 7/100). From the SIMS data, the doping concentration is all about 1020cm-3. The activation energy is decreased from 0.35 eV to 0.12 eV as the dopant concentration increased from 0.8×10 20cm-3 to 4.7×10 20cm-3. From the Hall measurements, the carrier mobility is about 2∼4 cm2/V. sec, and the carrier concentration is the 0.5∼1% of the dopant concentration. The gain boundary trap density predicted by the trapping model is about 4×l013cm” 2-2