MPCVD Diamond Lateral Growth Through Microterraces to Reduce Threading Dislocations Density

Abstract

Diamond lateral growth is a useful technique to assess 3D architectures of devices. The requirement of the overgrowth on etched substrates has been observed to have additional benefit in the crystallinity of the diamond. The surface roughness is enhanced and threading dislocation density is reduced as a consequence of the lateral growth on patterned substrates. Under these premises, this contribution presents a study of defects and terrace coalescences for the lateral growth on a trenched surface substrates with different trench widths. The latter was achieved on 100-oriented HPHT diamond substrates grown by MPCVD and using very thin-doped layers to mark the growth plane every 100 nm. The results showed high density of threading dislocations that were gathered to the centre of the coalescence. These threading dislocations, as well as planar defects, were investigated using transmission electron microscopy. The mechanism of those defects generation and the better conditions to achieve defect-free areas are discussed.