Growth And Research On AlN Deposited On The Si(111) Substrate

The band gap of AIN is6.2eV, which is much bigger than most of the other semiconductor martial. AIN also has great advantages in its saturation drift velocity of carrier, critical breakdown field, thermal conductivity, piezoelectric properties, radiation resistance and fine thermal stability. So AIN material has a broad application prospects in the field of high-power device, radioresistant device and UV detector. Many of the substrates martial including Si can be used in the epitaxy of AIN。Also facing many difficulties, the study of AIN deposed on Si substrate is still become the hot point, for it can be compatible with the mature Si integrated circuit technology. In this work, AIN with a crystal orientation of (0001) has been deposed on Si (111) substrate and the main tasks are as follows.1. AIN thin film has been grown on Si (111) substrate by MOCVD. The orientation of the AIN thin film is (0001), and the unfilmed area can be found within the filmed area. The optimized temperature for the growth is1400℃. Film coverage increases from70.3%to76.9%while the growth time rises from60min to160min.2. Samples with the different nucleating layers growth time or nucleating layers V/III ratio have been prepared. Film coverage increases from48.4%to67.4%while the growth time of the nucleating layer rises from Omin to12min. And Film coverage increases from70.5%to73.6%while the Ⅴ/Ⅲ ratio of nucleating layer rises from131to785.3. AIN has been grown under the lower growth rate of1nm/min. The SEM result shows that the morphology of the sample becomes much smooth and the unfilmed area disappears. This finding can be used as a basis for future research.