Optimal activation condition of nonpolar a-plane p-type GaN layers grown on r-plane sapphire substrates by MOCVD
✍ Scribed by Ji-Su Son; Kwang Hyeon Baik; Yong Gon Seo; Hooyoung Song; Ji Hoon Kim; Sung-Min Hwang; Tae-Geun Kim
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 874 KB
- Volume
- 326
- Category
- Article
- ISSN
- 0022-0248
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✦ Synopsis
The optimal conditions of p-type activation for nonpolar a-plane (1 1 -2 0) p-type GaN films on r-plane (1 -1 0 2) sapphire substrates with various off-axis orientations have been investigated. Secondary ion mass spectrometry (SIMS) measurements show that Mg doping concentrations of 6.58 Â 10 19 cm À 3 were maintained in GaN during epitaxial growth. The samples were activated at various temperatures and periods of time in air, oxygen (O 2 ) and nitrogen (N 2 ) gas ambient by conventional furnace annealing (CFA) and rapid thermal annealing (RTA). The activation of nonpolar a-plane p-type GaN was successful in similar annealing times and temperatures when compared with polar c-plane p-type GaN. However, activation ambient of nonpolar a-plane p-type GaN was clearly different, where a-plane p-type GaN was effectively activated in air ambient. Photoluminescence shows that the optical properties of Mg-doped a-plane GaN samples are enhanced when activated in air ambient.