DLTS and MCTS analysis of the influence of growth pressure on trap generation in MOCVD GaN

We demonstrate with DLTS and MCTS how changing growth pressure during MOCVD growth of GaN affects the majority and minority carrier trap signatures. Results indicate which specific traps are most strongly connected with the increased carbon concentration that lower growth pressure has led to. Carbon concentration is also verified with SIMS measurements. DLTS and MCTS measurements, related to carrier thermalization from traps, made up to a temperature of 450 K have found four majority carrier and two minority carrier traps. Using a lower growth pressures, at which greater incorporation of carbon is possible, has lead to larger concentrations of most of the traps; just as others have observed. However, the trap at EC − 0.48 eV is the least affected by the growth pressure. We relate all the traps found from DLTS and MCTS to those identified by others and mention the constituent atoms that the research community identifies with these traps.

► DLTS, MCTS and SIMS analyses were performed on MOCVD grown GaN. ► Four majority carrier traps and two minority carrier traps are identified. ► Carbon related trap signatures related to different growth pressures are discussed. ► DLTS data indicates reduced growth pressure leads to increased carbon trap density.