Structure of unepitaxial crystallites in a homoepitaxial diamond film

Unepitaxial crystallites (UC, non-epitaxial crystallites) were spontaneously grown in a homoepitaxial diamond film deposited by chemical vapor deposition (CVD) method at a high growth rate. Degradation of electrical and optical properties of the deposited films was attributed to the growth of the UC. In order to investigate the structure of the UC, electron microscopic analysis was performed on the UC. Focused ion beam thinning (FIB), a field emission scanning electron microscopy (FESEM) and a high-resolution transition electron microscopy (HRTEM) were employed for the investigation. Dislocations were observed in the growth region in the < 001 > direction. Nanometer-sized grains were observed in the growth region in the < 111 > direction. Most of the grains rotated by 70.53 degrees around the < 110 > axis, corresponding to Sigma3 coincidence site lattice (CSL) relation. Tbe (111) Sigma3 grain boundary was dominant in number and was extremely long in length. Incoherent Sigma3 boundaries connected to the {111} Sigma3 boundary were much shorter. (C) 2001 Elsevier Science B.V. All rights reserved.