Growth Of Gan Films On Gaas (100) Substrate By Rf-Sputtering And E-Beam Evaporation Techniques
| dc.contributor.author | Md Taib, Muhamad Ikram | |
| dc.date.accessioned | 2017-01-27T02:49:03Z | |
| dc.date.available | 2017-01-27T02:49:03Z | |
| dc.date.issued | 2016-04 | |
| dc.description.abstract | This work studies the structure, morphology and optical properties of GaN layer grown on porous GaAs/GaAs substrate by radio frequency (RF) sputtering and electron beam (e-beam) evaporation. For comparison, the GaN layer was also grown directly on GaAs substrate and nitride based buffer layers, i.e. aluminum nitride (AlN) and titanium nitride (TiN). In the first part of this work, the best parameters used to obtain good quality porous GaAs on GaAs substrate with uniform distribution and density were determined. It was found that uniform distribution and high density of pores can be fabricated with a mixed solution of dimethylformamide (DMF) and sulphuric acid (H2SO4) with 75% DMF concentration for 10 minutes, at a current density of 250 mA/cm2. In the next stage, the GaN layer was grown separately on different surfaces using RF-sputtering and e-beam evaporation. The evidence of Ga-N bondings inside the GaN layer was observed by XPS measurement. Overall, the GaN layers grown by RF-sputtering exhibited smoother surface as compared to one grown by e-beam evaporation, regardless of the surface growth. However, the measurement related to the structural and optical properties of GaN revealed that all GaN layers were amorphous in structure. To address this issue, post-annealing treatment at 980ÂșC for 10 minutes in ammonia (NH3) ambient was done on the samples. It was found that the annealed GaN samples were in polycrystalline structure. The rougher surface of the annealed GaN samples were rougher than the non-annealed GaN layers due to the formation of facetted grains with different symmetry. The annealing of the e-beam evaporated GaN layer on the porous GaAs/GaAs substrate with 75% DMF concentration showed the best improvement in morphological, structural and optical properties. In another experiment, porous GaN was fabricated on the RF-sputtered GaN layer for 3 minutes and 5 minutes, respectively, with and without the insertion of AlN buffer layer. Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) measurements showed that the 3 minutes-etched porous GaN/GaN without the AlN buffer layer exhibited more uniform pore distribution and higher pore density compared to its counterparts, despite of the large surface roughness. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3609 | |
| dc.language.iso | en | en_US |
| dc.publisher | Universiti Sains Malaysia | en_US |
| dc.subject | E-beam evaporation | en_US |
| dc.title | Growth Of Gan Films On Gaas (100) Substrate By Rf-Sputtering And E-Beam Evaporation Techniques | en_US |
| dc.type | Thesis | en_US |
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