A Study Of Ohmic Contact Of GaN And Its Devices

This work was supported by the State Science and Technology Ministry of the P. R. China under the contact No.G20000683-06,and by the National Natural Science Foundation of P. R. China under grant No. 60046001.Recently,Gallium Nitride (GaN) as a wide band gap semiconductor has attracted more and more attention and advanced rapidly,mainly due to its promising applications in short-wave light-emitting devices,photodetectors,as well as anti-radiation,high frequency and high power electronic devices. Up to date,it is still very hard to grow GaN bulk crystals,so the heteroepitaxial growth of high quality GaN thin films is the premise for the development of GaN-based devices. At the same time,the rapid progress on devices requires better ohmic contact between metals and GaN,so much more research work must be carried out at once.In this thesis,we presented a total review of the research history and currentstatus of GaN material and tbp devices. The primary investigation of this paper is theohmic contact between metafs'and GaN. Moreover,we have prepared photodetectorsand Schottky diodes based on GaN.The main work in this thesis includes two contents as follow:1 We have investigated the properties of ohmic contact between metal electrode (Al and Ti/Al electrode) and n-GaN dealed under different annealing conditions. By using XRD SIMS analytic methods and I-V measuremnet,we analysed the interface between metals and GaN,and suggested that it is effect to decrease the value of the ohmic contact. And we have built a system for testing the ohmic contact between metals and semiconductor materials.2 We prepared photodetectors based on GaN/Si and GaN/ Al2O3 and Schottky diodes on GaN/Al2O3. Some basic research about these devices has been done.