Heat Treatment with High-Pressure H₂O Vapor of Pulsed Laser Crystallized Silicon Films

Abstract

Improvement of electrical properties for 7.4 ×10 17 cm -3 phosphorus-doped pulsed laser crystallized silicon films of 50 nm thickness formed on quartz glass substrates was achieved by heat treatment with high-pressure H 2 O vapor. The electrical conductivity was increased from 1.3 ×10 -5 S/cm (as-crystallized) to 2 S/cm by annealing at 270°C for 3 h with 1.3 ×10 6 Pa H 2 O vapor. The spin density of undoped laser crystallized silicon films was reduced from 1.6 ×10 18 cm -3 (as-crystallized) to 1.2 ×10 17 cm -3 by annealing at 310°C for 3 h with 1.3 ×10 6 Pa H 2 O vapor. Theoretical analysis revealed that the potential barrier height at grain boundaries decreased from 0.3 eV (as-crystallized) to 0.002 eV. High-pressure H 2 O vapor annealing offer the possibility of reducing the density of defects states through oxidation of the defects at low temperature.