Shallow-Junction Formation by Rapid Thermal Diffusion into Silicon from Doped Spin-on Glass Films

Abstract

ABSTRACTHere we investigate the possibility to use rapid thermal annealed spin-on doped glass (SOG) films as a doping source as well as a surface passivation layer. The dilution of the SOG liquid source with methanol allows to control the oxide film thickness and the dopant concentration. The results show that the combination of spin-on film (after dilution) and RTP can produce shallow lightly doped emitters. Junction depths less than 0.2 µm and surface concentrations in the range 1−20 × 1019 cm−3 are obtained. Sheet resistances lower than 150 Ω/□ are easily reached. Moreover, the minority-carrier diffusion length is improved due to the gettering effect induced by phosphorus diffusion. The use of the remaining SOG oxide film as a passivation layer makes this technique favourable for some application.