The roles of N and P type Si(100) substrates in the nucleation and growth of textured diamond films by hot filament chemical vapor deposition

Abstract

Comparison study of nucleation and growth characteristics of chemical-vapor-deposited diamond films on CoSi 2 (001) and Si(001) P-Si(100) and n-Si(100) substrates had quite different responses to the same process parameters used in the modified four-step diamond growth method, i.e., pretreatment, heating, bias enhanced nucleation ͑BEN͒ and bias texture growth ͑BTG͒, which has been developed to grow textured diamond films by hot filament chemical vapor deposition. At the pretreatment step, a bright blue plasma discharge induced the formation of damaged voids randomly distributed on the surfaces of p-Si(100) and n-Si(100). The damaged voids on p-Si(100) are several microns in size and 3 m in depth. In contrast, the size and depth of the damaged voids on n-Si(100) are in nanometer scale, approximately two orders of magnitude lower than those on p-Si(100). At the BEN step, carburization occurred along with the possibility of diamond nucleation. Unfacet nuclei of micron scale distributed around the edge of damaged voids all over the p-Si(100) substrate. In contrast, a great number of small nuclei of nanometer scale spread and covered all the damaged voids around the outer edge of the n-Si(100) substrate. The continuous textured diamond film grown on p-Si(100) had better diamond quality than that on n-Si(100) at the BTG step. The textured diamond film on p-Si(100) was flat, however, that on n-Si(100) was under stress in convex shape. Ion bombardment at the BTG step resulted in the enhancement of the growth of textured diamond and in the degradation of diamond quality through the formation of amorphous carbon. P-Si(100) is considered better than n-Si(100) to be the substrate for textured diamond deposition.