Precursors for carbon doping of GaN in chemical vapor deposition

Abstract

Articles you may be interested in 3 ] have been investigated as precursors for intentional carbon doping of (0001) GaN in chemical vapor deposition. The carbon precursors were studied by comparing the efficiency of carbon incorporation in GaN together with their influence on morphology and structural quality of carbon doped GaN. The unsaturated hydrocarbons C 2 H 4 and C 2 H 2 were found to be more suitable for carbon doping than the saturated ones, with higher carbon incorporation efficiency and a reduced effect on the quality of the GaN epitaxial layers. The results indicate that the C 2 H 2 molecule as a direct precursor, or formed by the gas phase chemistry, is a key species for carbon doping without degrading the GaN quality; however, the CH 3 species should be avoided in the carbon doping chemistry.

Carbon doped GaN buffer layer using propane for high electron mobility transistor applications: Growth and device results

“…In a recent study, 9 we identified several potential carbon containing gases that could be used for in-situ carbon doping of GaN.…”

Study of GaN doping with carbon from propane in a wide range of MOVPE conditions

“…Most interesting is the evaluation of the effect of growth rate on carbon concentration. In work [5] (and likely in [6,7]), the growth rate of GaN:C epilayers was only 0.65 μm/h. This value is too low for production.…”

“…These works are a significant step in the development of controllable carbon doping of gallium nitride. However, in the recent works [6][7][8], the authors have focused on properties of device structures while the main objective of paper [5] was a comparison of carbon incorporation efficiency for a number of carbon precursors and growth temperature was the only parameter studied. An observed tendency -increase of carbon concentration with temperature reduction -was the same as for background carbon doping.…”

“…It was reported [5] that high-quality GaN:C epilayers may be grown using a number of hydrocarbons as dopants. Later the same team demonstrated HEMTs with GaN:C buffer intentionally doped from propane [6,7] and quite recently similar results were published by another group [8].…”

Floating body effects in carbon doped GaN HEMTs

“…Carbon impurities are always present as a contaminant in MOCVD grown GaN, but modifying the growth conditions or adding an external source can increase the concentration above 10 19 cm -3 [5]. The carbon can be substituted on either the Ga or N site and can form a variety of complexes, with each species having different trap characteristics.…”