On compensation and impurities in state-of-the-art GaN epilayers grown on sapphire

Book · Fri Nov 01 04:00:00 EST 1996

OSTI ID:395020

Wickenden, A E; Gaskill, D K; Koleske, D D ^[1]; Doverspike, K ^[2]; Simons, D S; Chi, P H ^[3]

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1. Naval Research Lab., Washington, DC (United States). Lab. for Advanced Material Synthesis
2. Hewlett-Packard, San Jose, CA (United States)
3. National Inst. of Standards and Technology, Gaithersburg, MD (United States)

A comparison between 300 K electron transport data for state-of-the-art wurtzite GaN grown on sapphire substrates and corresponding theoretical calculations shows a large difference, with experimental mobility less than the predicted mobility for a given carrier concentration. The comparison seems to imply that GaN films are greatly compensated, but the discrepancy may also be due to the poorly known values of the materials parameters used in the calculations. In this work, recent analysis of transport and SIMS measurements on silicon-doped GaN films are shown to imply that the compensation, N{sub A}/N{sub D}, is less than 0.3. In addition, the determination of an activation energy of 34 meV in a GaN film doped to a level of 6 {times} 10{sup 16} cm{sup {minus}3} suggests either that a second, native donor exists in the doped films at a level of between 6 {times} 10{sup 16} cm{sup {minus}3} and 1 {times} 10{sup 17} cm{sup {minus}3}, or that the activation energy of Si in GaN is dependent on the concentration, being influenced by impurity banding or some other physical effect. GaN films grown without silicon doping are highly resistive.

• OSTI ID: 395020
• Report Number(s): CONF-951155--; ISBN 1-55899-298-7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
ALUMINIUM NITRIDES
AMMONIA
CARRIER DENSITY
CARRIER MOBILITY
CORRELATIONS
DOPED MATERIALS
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EXPERIMENTAL DATA
GALLIUM NITRIDES
HALL EFFECT
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
ORGANOMETALLIC COMPOUNDS
SEMICONDUCTOR MATERIALS
SILICON
VAPOR PHASE EPITAXY