The role of carbon in transport processes during PVT growth of bulk GaN

Abstract

Thick GaN layers were deposited by the reaction of gallium with ammonia. The Physical Vapour Transport (PVT) process with NH3 addition is characterized by moderate NH3 flow rates, pressures, and consumption of reactants, by reduced parasitic growth and no NH4Cl formation. Carbon addition to the ammonia results in growth of thicker layers at increased transport rate and in single crystals even at Ga super saturations, which would normally be too high for single crystalline growth. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Pseudohalide vapour growth of thick GaN layers

“…Our studies on the growth of GaN crystals by the direct synthesis from elemental Ga and ammonia [15,16] essentially provided identical results. However, further observations lead us to suppose that the overall reaction (3) is not the only one, maybe even not the dominating one under certain circumstances.…”

Microscopic lateral overgrowth by physical vapour transport of GaN on self‐organized diamond‐like carbon masks

“…GaN layers are grown by Cl-free physical vapour transport (see for details [4,5]) an alternative of the wellestablished HVPE method [6,7]. Prior to PVT growth an amorphous carbon layer was in-situ deposited on a MOCVD-(0001) GaN/(0001) sapphire template.…”

A new approach to grow C‐doped GaN thick epitaxial layers

“…In the series of experiments discussed some parts of the growth equipment were made of carbon and served as a source of carbon in the growth atmosphere. During the growth process gallium was evaporated from the heated melt at elevated temperatures (1250-1450 °C) [1] and transported to the seeding crystal (crystalline buffer layer on an Al 2 O 3 or SiC substrate). The Ga transport was controlled by the temperature of the Ga source (melt), the flow-rate of the nitrogen carrier gas through the crucible area, and by the amount of carbon [1].…”

“…During the growth process gallium was evaporated from the heated melt at elevated temperatures (1250-1450 °C) [1] and transported to the seeding crystal (crystalline buffer layer on an Al 2 O 3 or SiC substrate). The Ga transport was controlled by the temperature of the Ga source (melt), the flow-rate of the nitrogen carrier gas through the crucible area, and by the amount of carbon [1]. The background atmosphere in the growth chamber was a mixture of nitrogen and hydrogen, which originated from the thermal decomposition of ammonia.…”