nvestigations of nitride films and GaN/InGaN heterostructures grown on sapphire or silicon substrates

• Main Authors: Ming Fa Yeh, 葉明發
• Other Authors: Jyh Rong Gong
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/54692045635543781594

碩士 === 逢甲大學 === 材料科學學系 === 87 === Nitride films and GaN/InGaN heterostructures were grown on sapphire or silicon substrates. MOCVD-grown n-GaN and p-GaN show electron and hole concentration of ~1018 cm-3 and ~1017 cm-3, respectively. Both n-GaN and p-GaN tend to release strain by introducing dopant atoms (Mg or Si). Mg-H complexes can be effectively activated by RTA process at 1050℃ for 45 sec in N2 ambient. InGaN films prepared by MOCVD have In content as high as 35%. Low temperature and high partial pressure of N2 are helpful in increasing In content. GaN/InGaN heterostructures were also grown on sapphire substrates by MOCVD. Bright-field cross-sectional TEM image shows the pulling effects in the InGaN film near the interfaces of GaN/InGaN heterostructures. ALE-grown AlN films were grown directly on Si substrates. High TMA flow rate or low temperature tends to result in Al droplets formation on the AlN surface. GaN films, which were grown on Si substrates by ALE, have better crystalline quality when deposited on AlN intermediate layer grown at high temperature than that of the films grown on AlN buffer layer deposited at low temperature. Both AlN and GaN films show polycrystalline nature when they are deposited on (001) Si. The best AlN film grown on Si (111) substrate shows a FWHM of 26 arcmin of the (0002) diffraction. The best GaN film grown on (111) Si substrate using AlN as the intermediate layer shows a FWHM of 45 arcmin of the (0002) diffraction.