Role of Hydrogen in the CVD of Wide Bandgap Nitride Semiconductors

✍ Scribed by Stephen J. Pearton; Alexander Y. Polyakov

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 386 KB
• Volume: 16
• Category: Article
• ISSN: 0948-1907
• DOI: 10.1002/cvde.201000041

✦ Synopsis

Hydrogen is an important component of the gas-phase growth chemistry for GaN, which is typically based on NH 3 and (CH 3 ) 3 Ga, and also the processing environment for subsequent device fabrication (e.g., SiH 4 for dielectric deposition, NH 3 or H 2 annealing ambients), and is found to readily permeate heteroepitaxial material at temperatures 200 8C. Its main effect has been the passivation of Mg acceptors in p-GaN through the formation of neutral Mg-H complexes, which can be dissociated through minority-carrier (electron) injection or simple thermal annealing. Atomic hydrogen is also found to passivate a variety of other species in GaN, as detected by a change in the electrical or optical properties of the material. The injection of hydrogen during a large variety of device fabrication steps has been detected by secondary ion mass sprectrometry (SIMS) profiling using 2 H isotopic labeling. Basically all of the acceptor species in GaN, i.e., Mg, C, Ca, and Cd, are found to form complexes with hydrogen.