The Study Of Epitaxial Growth Of Gan Materials Based On Magnetron Sputtering Aln

In recent years,since the first Gallium nitride(GaN)based electronic devices were introduced,GaN-based electrons and light-emitting devices have achieved unprecedented development.However,the price of GaN homogeneous substrate has prompted people to turn their attention to the process of heteroepitaxial method to obtain high quality GaN materials.Among them,Si-based materials have become the first choice for GaN heteroepitaxial method due to their mature process,low price,good electrical characteristics and thermal conductivity.At present,metal oxide vapor phase epitaxy(MOCVD)has become a mainstream market-approved GaN material epitaxy method due to its high performance and mass production.In order to avoid the remelting between GaN material and Si-based substrate,a layer of Aluminum nitride(AlN)is always grown as a nucleation layer and a buffer layer in situ.However,due to the high temperature characteristics of the growth process of AlN and GaN,the equipment requires a lot of time for the temperature rise and fall operation,and the high temperature process also introduces a severe thermal mismatch between the AlN and the Si-based substrate,which causing cracks in the epitaxial wafer during the cooling and then lower the production yield.As a kind of physical deposition,magnetron sputtering has a wide range of applications in vapor deposition of metals due to its low operating temperature and high production efficiency.If the AlN buffer layer with preferential orientation can be deposited on the Si(100)substrate by the method of magnetron sputtering,not only the thermal stress introduced by the high temperature of the MOCVD can be avoided,but also the production efficiency can be greatly improved.Therefore,the research on magnetron sputtering AlN on Si substrate is not only of academic value,but also has great application value for the industry.In this thesis,the research work mainly focuses on the magnetron sputtering deposition of AlN on Si(100)substrate and the epitaxial of GaN.Based on the analysis of theoretical and experimental results,the process window is continuously optimized,and finally the highly optimized AlN buffer layer is obtained.On the basis of this,a high crystal quality GaN material is epitaxially grown.The main contents of the paper are as follows:1.Research on the window of AlN process by magnetron sputtering deposition.It mainly includes the reaction chamber pressure,power supply and reaction gas ratio in the sputter deposition process.2.AlN stress state study.In order to meet the needs of GaN epitaxy,we have carried out a series of research and analysis on the residual stress state of AlN films.3.Research on GaN epitaxial window and GaN nucleation mechanism.we mainly optimize the temperature and V/III of the epitaxial process and found that the epitaxial GaN morphology on two different substrates(magnetron sputtering AlN and MOCVD epitaxial AlN)is very different,so the evolution and mechanism of the nucleation stage are explored.4.GaN epitaxial structure optimization.On the basis of the above,we added a layer of MOCVD epitaxial AlN as the transition layer.After optimizing the thickness of the transition layer,the surface morphology and crystal quality of GaN were significantly improved.