nvestigation of High Quality GaN on Si (111) Substrate by Using Nitride Buffer Layer

• Main Authors: Shih-Yu Chih, 邱仕宇
• Other Authors: Li-Jen Chou
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/41383913371137131095

碩士 === 國立清華大學 === 材料科學工程學系 === 91 === Abstract III-V nitride has attracted much attention in the late 20th century because of its many merits such as tunable direct band gap which cover the lasing wavelength from 300nm to 800nm, highly reliable device property in harsh environment (high temperature) and high luminescence efficiency. It can be made for optical data storage device, high frequency device (RF), and high brightness LED or LD. To take advantage of well matured silicon microelectronic technology, using Si as a substrate to grown high quality GaN film maybe a shortcut to realize the optoelectronic integrated circuitry (OEIC). In this thesis, searching an ideal buffer layer to mitigate the large lattice mismatch between GaN and Si as well as to stop Si inter-diffusion, using HRTEM, PL, SEM and Auger measurements, we successfully identified a diffusion inhibition layer (DIL) which serves the about two reasons quite well. In the first part of the thesis, HRTEM was used to explain the differences of the atomic scale microstructure between NH3 nitridied β-Si3N4 and N2 plasma one. Data indicated that β-Si3N4 formed by plasma enhanced method showed better interfacial properties. HRTEM studies showed that the length of c-axis for β-Si3N4, was more severely elongated by thermal nitridized method. C-V measurements revealed that the fast interface state (Dit) is low for the interface betweenβ-Si3N4 formed by plasma enhanced method and Si substrate. In the second part of the thesis, we studied the thickness effect of the AlN buffer layer in the GaN/AlGaN/AlN/Si growth structure. The results indicated that 25nm of AlN is the best choice for the thickness, either thinner or thicker of the AlN will deteriorate the above GaN optical and physical properties. In the last portion of the thesis, a diffusion inhibition layer was characterized by advanced HRTEM technique. By using EDS mapping method, we reported first time that this DIL can stop the Si inter-diffused to the GaN layer; meanwhile, we discovered defects or dislocations will enhance the Si interdiffusion by EDS line scan spectroscopy. PL and Raman measurements also indicated the better optical and physical properties have been obtained by applying the DIL in between the GaN and Si.