K. Volz et al., Heteroepitaxial SiC films grown in Si by CH4 plasma immersion ion implantation: Conditions and mechanisms of their formation, NUCL INST B, 175, 2001, pp. 569-574
Thin SiC films in Si are formed by pulse biasing a Si wafer to a high volta
ge in a methane (CH4) RF plasma (plasma immersion ion implantation, PIII).
The composition and structure of the resulting layers in dependence on the
preparation conditions - mainly the implantation temperature - are elucidat
ed by means of Rutherford backscattering spectrometry (RBS), nuclear resona
nce analysis (NRA) for hydrogen depth profiling and transmission electron d
iffraction (TED). It is shown that by using PIII all C/Si ratios from 0 to
1/0 can be obtained. The hydrogen, which is implanted from the precursor ga
s as well, has a depth profile, which is not a typical implantation profile
. Rather, the hydrogen depth profile is chemically governed by the carbon d
epth distribution. SiC with its stoichiometry close to unity can trap by fa
r the most hydrogen. Increasing or lowering the C/Si ratio results in a dec
reasing trapping possibility for hydrogen. The hydrogen depth profile for S
iC films also depends strongly on the implantation temperature. Films witho
ut hydrogen contamination can be grown at 850 degreesC. TED shows that thes
e films grow heteroepitaxially aligned with the Si matrix. (C) 2001 Elsevie
r Science B.V. All rights reserved.