Shallow n⁺ Junctions in Silicon by Arsenic Gas-Phase Doping

Shallow arsenic junctions were formed in short processing times using gas-phase rapid thermal diffusion with arsine or tertiarybutylarsine (TBA). A 60 s gas-phase diffusion at 1100°C using 3.6% arsine in helium at 760 Torr formed 150 nm junctions with a measured sheet resistance of 100 Ω/□. Shallow junctions were also formed with a 12 min diffusion at 900°C using 10% TBA in argon at 10 Torr. These TBA-formed junctions have arsenic concentration at the silicon surface greater than 1 X 1O20 atms/cm3 and a sheet resistance of 244 Ω/□. In addition, TEM cross sections show no process-induced damage at the junction for gas-phase doping. © 1994, The Electrochemical Society, Inc. All rights reserved.