Accession Number : ADA132988

Title :   Evaluation of Gallium Nitride for Active Microwave Devices.

Descriptive Note : Final rept. Jun 81-Sep 82,


Personal Author(s) : Gershenzon,M

PDF Url : ADA132988

Report Date : Jul 1983

Pagination or Media Count : 52

Abstract : Low temperature photoluminescence results that donors in GaN are relatively shallow, so that low resistivity n-type material at room temperature is easily achieved. However, all 'shallow' acceptors are quite deep, so that low resistivity p-type material is not possible. Thus, high current density, p-n junctions are not feasible. A native shallow donor, probably a simple nitrogen vacancy, is present in all GaN crystals grown, whether by VPE, MOCVD, and from these results, by MBE. It is present in the range 10 to the 18th power to 10 to the 20th power per cu cm. This doping level is much too high for it to be used in the drift region of an IMPATT device. Its value can be reduced by compensation with acceptors. But this also lowers the mobility, leading to an increase of the required electric field to attain saturated drift velocity, thus negating the advantage. The native donor density cannot be reduced by altering growth conditions in VPE, MOCVD or MBE growth. It can, however, be somewhat reduced by ion implantation of N(+) ions, followed by a specified anneal. This, however, leads to a meta-stable situation wherein device degradation seems highly likely. Thus, in spite of its theoretical potential, GaN may not be a good candidate as a material for transit-time-limited, power microwave amplifiers. (Author)

Descriptors :   *Band theory of solids, *N type semiconductors, *Nitrides, *P type semiconductors, *Gallium compounds, *Charge carriers, *Electron acceptors, Photoluminescence, Doping, Impatt diodes, Electric fields, Microwave equipment, Electrical resistance, Ion implantation, Shallow depth, Environments, Ions, High power, Growth(General), Regions, Low temperature, Power amplifiers, Saturation, Room temperature, High density, Degradation, Velocity, Drift, Materials

Subject Categories : Electrical and Electronic Equipment
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE