N-Limited Versus Ga-Limited Growth on${\rm GaN}(000\bar{1})$by MBE UsingNH3

R. Held, D. E. Crawford, A. M. Johnston, A. M. Dabiran and P. I. Cohen
Additional contact information
R. Held: Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
D. E. Crawford: Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
A. M. Johnston: Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
A. M. Dabiran: Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
P. I. Cohen: Department of Electrical Engineering, University of Minnesota, Minneapolis, MN 55455, USA

Surface Review and Letters (SRL), 1998, vol. 05, issue 03n04, 913-934

Abstract: GaN was grown on${\rm GaN}(000\bar{1})$by MBE usingNH3and a Ga Knudsen cell. The growth kinetics on samples of this polarity were investigated with desorption mass spectroscopy (DMS) and reflection high energy electron diffraction (RHEED). Both techniques were used to observe and control surface termination, Ga condensation and surface temperature. GaN growth and decomposition rates were measured by DMS. Two stable surface terminations were found to exist — N-terminated and Ga-terminated${\rm GaN}(000\bar{1})$. The N-terminated surface also contained hydrogen which desorbed during growth at a rate proportional to the growth rate. Low temperature reconstructions were only observed by adding weakly adsorbed Ga on top of the Ga-terminated surface. During growth two distinct growth regimes were identified: growth under excessNH3and growth under excess Ga. Growth is limited in both regimes by GaN decomposition at high temperatures with an activation energy of 3.4 eV. Growth in the excess Ga regime ceased below the Ga condensation temperature. Under conditions of excessNH3, strong but damped oscillations in the specular RHEED intensity were observed on smooth surfaces. Contrary to previous suggestions, the period of these oscillations did not correspond exactly to integral layer deposition and was not characteristic of a narrow growth front. Further, the growth mode changed from island nucleation to step flow with an activation energy of 1.2 eV. Under conditions of excess Ga, the diffraction was 2-D but RHEED intensity oscillations were not observed, indicating a step flow growth mode. In this latter regime RHEED measurements were very sensitive to termination changes on the${\rm GaN}(000\bar{1})$surface, and the growth rate was found to decrease linearly with increasing Ga flux. This reduction is explained by a model in which weakly adsorbed Ga blocks reaction at strongly bound Ga. A map is presented to provide a framework for categorizing the overall growth.

Keywords: 6855; 81.51; 61.14H (search for similar items in EconPapers)
Date: 1998
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.worldscientific.com/doi/abs/10.1142/S0218625X98001274
Access to full text is restricted to subscribers

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:wsi:srlxxx:v:05:y:1998:i:03n04:n:s0218625x98001274

Ordering information: This journal article can be ordered from

DOI: 10.1142/S0218625X98001274

Access Statistics for this article

Surface Review and Letters (SRL) is currently edited by S Y Tong

More articles in Surface Review and Letters (SRL) from World Scientific Publishing Co. Pte. Ltd.
Bibliographic data for series maintained by Tai Tone Lim ().