Ion implantation of microcrystalline silicon for low process temperature top gate thin film transistors

Ion implantation of phosphorus was used to dope amorphous and microcrystall ine silicon with the aim of achieving a low-temperature, self-aligned proce ss for forming n(+) contacts to top-gate thin-film transistors. Amorphous a nd microcrystalline films made with both RF glow discharge and hot-wire che mical vapor deposition were implanted. The effect of the dose, energy and i mplantation temperature and subsequent annealing at increasing temperatures on the dark conductivity, activation energy and photoconductivity were stu died. Lowering the energy (15 keV) while increasing the dose (10(15) cm(-2) ) and the implantation temperature (300 degrees C) resulted in the highest after anneal (300 degrees C) dark conductivity for both hot-wire (0.3 Ohm(- 1)cm(-1)) and RF (0.2 Ohm(-1) cm(-l)) microcrystalline films. (C) 1999 Else vier Science S.A. All rights reserved.