Gan Heteroepitaxial The Initial Growth Conditions Optimization And Its Real-time Monitoring

GaN, the third generation of semiconductor material, becomes the hot point of research because of its excellent characteristics. It has wide potential application and development in the fields of microelectronics and optoelectronicsThis thesis comes from the National Natural Science Fundation (69976008), the title is "Research on growth of self-organized GaN quantum dots structures by ECR-PEMOCVD and its characteristics". According to the principle of growing self-organized quantum dots structures, we have to grow an layer of A1N with fairly good crystal quality before the growth GaN quantum dots. Due to the temperature limitation of the heater of our device, however we have accumulated some useful experience on the growth of GaN, so we decide to grow a GaN epilayer before growing A1N epilayer. Because of the difference between the lattice constants of A1N and GaN is smaller, we think the A1N epilayer with fairly good crystal quality on the GaN epilayer can be obtained easily.One of major work of this thesis is to find the optimized procedure parameters of the initial growth (hydrogen plasma cleaning, nitridation and buffer growth) of GaN hetero-epitaxy on sapphire substrate based on the theory of film growth and by using of the ECR-PEMOCVD technology. The semiconductor growth device is ESPD-U (ECR Semiconductor Processing Device - Upgrade) developed by our group. The RHEED, XRD, AFM were used to measure the crystalline characteristics of sample for comparison. We have primarily obtained an optimized growth condition of the cleaning time and temperature of plasma cleaning, nitrogen flow rate and time of nitridation, the V/III ratio and temperature during buffer growth after large amount experiments in our group. And we have got the fairly flat GaN epilayer with good crystal quality.The second major work is to design a set of real-time monitoring system (hardware and software) of semiconductor film growth for the ESPD-U device according to the characteristics of the growth procedure and under the collaboration with the Electronic and Information Institute of our university. The practical operation of this real-time monitoring system shows that the growth process can run continuously and stably, the reproducibility of growth process can be improved and the intension of experimentalists can be reduced. So the anticipative purpose has been realized.This thesis is supported by the National Natural Science Fundation (69976008).