Control of surface and bulk crystalline quality in single crystal diamond grown by chemical vapour deposition

Abstract

In order to improve the performance of existing technologies based on single crystal diamond grown by chemical vapour deposition (CVD), and to open up new technologies in fields such as quantum computing or solid state and semiconductor disc lasers, control over surface and bulk crystalline quality is of great importance. Inductively coupled plasma (ICP) etching using an Ar/Cl gas mixture is demonstrated to remove sub-surface damage of mechanically processed surfaces, whilst maintaining macroscopic planarity and low roughness on a microscopic scale. Dislocations in high quality single crystal CVD diamond are shown to be reduced by using substrates with a combination of low surface damage and low densities of extended defects. Substrates engineered such that only a minority of defects intersect the epitaxial surface are also shown to lead to a reduction in dislocation density. Anisotropy in the birefringence of single crystal CVD diamond due to the preferential direction of dislocation propagation is reported. Ultra low birefringence plates (< 10 -5 ) are now available for intra-cavity heat spreaders in solid state disc lasers, and the application is no longer limited by depolarisation losses. Birefringence of less than 5×10 -7 along a direction perpendicular to the CVD growth direction has been demonstrated in exceptionally high quality samples. † Corresponding author 2 of 25 1.

Characterization of Single-Crystal Synthetic Diamond for Multi-Watt Continuous-Wave Raman Lasers

“…Recent developments in chemical vapour deposition growth have led to material with low birefringence and low absorption through the minimisation of the dislocation density and nitrogen impurities respectively [20,21]. This has made the intracavity use of diamond in solid-state lasers more practical -as a heat spreader [28,29] and in Raman lasers [11,[15][16][17][18].…”

“…For diamond, this figure of merit is over two orders of magnitude higher than for KGW based on typically available lengths. Such advantages, coupled to the recent improvements in the optical quality of synthetic single crystal diamond [11,20,21] have motivated the recent interest in diamond for Raman lasers. In this paper the properties of diamond will be experimentally assessed in the context of continuous-wave intracavity Raman lasers, using KGW as a standard for comparison.…”

“…As a result there is considerable interest in the use of diamond as a Raman laser material, both in pulsed [15][16][17] [11,18]. This work is motivated by the exceptional thermal properties of diamond [19] and enabled by the recent development of high optical quality synthetic diamond grown by chemical vapour deposition [11,20,21]. In this paper, modern synthetic single-crystal diamond will be compared with KGW, a representative conventional Raman laser crystal.…”

Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

“…The hillock formation is believed to be caused by stacking faults or dislocations that nucleate at the interface between the surface and the epitaxial layer from lattice defects or propagate from the substrate into the CVD layer [31,32]. Those defects induce a surface roughness, facilitate incorporation of impurities, crystalline imperfections, and non-diamond phases.…”

Lumineszcencia centrumok kialakítása és spektrális jellemzése nanogyémántban

“…Nemrégiben olyan kettőstörés-mentes, jó minőségű gyémántokat sikerült előállítani [20], amelyek a lézerekben intrakavitációs hőelosztóként (a gyémánt kiváló hővezető képességének köszönhetően) alkalmazhatóak. A gyémánt Raman-lézer aktív anyagaként is kiváló.…”