Investigations on doping of amorphous and nanocrystalline silicon films deposited by catalytic chemical vapour deposition

Hydrogenated amorphous and nanocrystalline silicon, deposited by catalytic chemical vapour deposition, have been doped during deposition by the additi on of diborane and phosphine in the feed gas, with concentrations in the re gion of 1%. The crystalline fraction, dopant concentration and electrical p roperties of the films are studied. The nanocrystalline films exhibited a h igh doping efficiency, both for n and p doping, and electrical characterist ics similar to those of plasma-deposited films. The doping efficiency of n- type amorphous silicon is similar to that obtained for plasma-deposited ele ctronic-grade amorphous silicon, whereas p-type layers show a doping effici ency of one order of magnitude lower. A higher deposition temperature of 45 0 degreesC was required to achieve p-type films with electrical characteris tics similar to those of plasma-deposited films. (C) 2001 Elsevier Science B.V. All rights reserved.