S. Barrat et al., Synthesis of highly oriented CVD diamond films by ultra short bias enhanced nucleation step, DIAM RELAT, 10(9-10), 2001, pp. 1637-1642
Highly oriented diamond films have been deposited on silicon substrate by t
he MPCVD technique (microwave plasma assisted chemical vapour deposition) u
sing an ultra short bias enhanced nucleation process (so called USBEN). We
focus our attention on two points: the homogeneity of the deposit in order
to perform a precise characterisation whatever surface location (on 1 X 1 c
m(2) of single silicon substrate); and the simplification of the successive
steps usually performed in the BEN process. This is carried out by optimis
ing the microwave cavity and the d.c. discharge extension and by keeping th
e pretreatments just necessary to obtain high nucleation density with an ac
ceptable epitaxial ratio and a good homogeneity. This leads to a drastic re
duction of the bias time of only 30 s for low bias voltage. As we obtain a
highly oriented diamond film with a short bias pretreatment without prelimi
nary carburation step, we discuss the substrate transformation under a weak
bombardment duration of ions having a quite low energy. We think that the
bias step probably consists to a slight modification of the substrate surfa
ce. (C) 2001 Elsevier Science B.V. All rights reserved.