In this thesis, we will discuss that GaN template which was grown on the sapphire by metal organic vapour phase epitaxy (MOVPE). Then GaN epi-layer, intrinsic AlGaN (as spacer) and N-type AlGaN(doping Si) which offers carrier grow by molecular-beam epitaxy. We changed the content of aluminium to find out any difference on AlGaN/GaN heterostructure .
For our experimental, we tried our best to keep all the parameters in steady besides the vapor of aluminum. If the vapor of aluminum every 4.65*10-9 torr is set to be one unit, then ratio of the pressure from sample A to E is 0.5, 1.0, 1.5, 2 and 3. We can get the best growth parameters by hall measurement, reflection high-energy electron diffraction, scanning electron microscope, atomic force microscopic and X-ray diffraction analysis to improve the quality of the sample.
From scanning electron microscope and reflecting high energy electronic diffraction picture, the roughness of all samples is good which confirms that the samples should be in two-dimensional (2D) growth mode. We can find the same result by atom force microscope. After comparing 3D picture, we find out the surface of Sample B is the smoothest, meanwhile the roughness is 1.404 (nm) has been calculated through the functions. Due to Hall measurement in 77 K, the electron mobility of this series of samples are very high, especially Sample C is 10995(cm2/Vs) and sample D is 10697 (cm2/Vs) respectively. Quite narrow Full Width at Half Maximum(FWHM) of AlGaN which is about only 300 (arcsec) has been showed under the analysis of X-ray in rocking curve mode and these results indicate these samples have extraordinary qualities better than previous one.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0722108-130755 |
| Date | 22 July 2008 |
| Creators | Su, Jui-yang |
| Contributors | Ming-Kuei Lee, Ikai Lo, Jih-Chen Chiang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0722108-130755 |
| Rights | not_available, Copyright information available at source archive |
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