Study On Preparation And Controllable Doping Of ?-Ga₂O₃ Films By MOCVD

?-Ga2O3 is one of the emerging ultra-wide band gap semiconductor materials in recent years.It has attracted wide attention because of its ultra-wide band gap of 4.2-4.9eV,high thermal stability and large-scale production of natural substrates.?-Ga2O3 has high breakdown electric field,low on-resistance,high Baliga's figure of merit,room temperature ferromagnetism and resistive properties.Combined with the current advanced material preparation and characterization technology,P-Ga2O3 is at the forefront of development in the fields of electronics(power devices),optoelectronics(light detection and light emitting devices)and sensing systems(application sensors).?-Ga2O3 single crystal can be directly obtained from melt growth method,and films can be prepared by various processes,as well as the increasingly perfect material characterization technology and the development of basic physics provide a reliable basis for the preparation of ?-Ga2O3 devices.In addition,the research on ?-Ga2O3 materials has also further promoted the intersection of engineering,computational and theoretical field.In recent years,though some key issues of ?-Ga2O3 materials have made great breakthroughs,the research on material preparation,property and related device applications is not deep enough.In particular,the quality of the ?-Ga2O3 films is still low,and the research on controllable doping is immature,making the performance of ?-Ga2O3 devices still far from practical applications.Aiming at the above two important issues,we used a high-temperature MOCVD system to conduct in-depth and detailed research on the preparation of?-Ga2O3 films and n-type doping.The specific research content and conclusions are as follows:1.The ?-Ga2O3 films were grown on c-plane sapphire substrates by MOCVD.Through comparative experiments,the process conditions which have great influence on the film properties were adjusted and optimized.The films prepared under different conditions were characterized,and the thermodynamics and kinetics of films growth were analyzed.By comparing the characteristics of different ?-Ga2O3 films,the best growth temperature and pressure of ?-Ga2O3 films were summarized.2.The ?-Ga2O3 films were grown by combining GaN high-temperature oxidation and MOCVD.The GaN films on the sapphire substrates were oxidized at a high temperature to form Ga2O3/GaN/sapphire templates firstly,and then the ?-Ga2O3 films were grown on the templates by MOCVD.The characteristics of the ?-Ga2O3 films prepared by the two methods were analyzed.By comparing with the conventionally grown ?-Ga2O3 films,it is found that the quality of the ?-Ga2O3 films grown on the Ga2O3/GaN/sapphire templates have been improved.3.Using silane as the n-type dopant,the n-type ?-Ga2O3 films were grown on the c-plane sapphire substrates and(100)direction ?-Ga2O3 single crystal substrates by MOCVD.The effects of silane flow rate and oxygen annealing time on the properties of ?-Ga2O3 films were studied in detail.The relationship between the carrier concentration of ?-Ga2O3 films and the silane flow rate and annealing time was obtained through experiments.Comparing the n-type ?-Ga2O3 films obtained on two different substrates,it is found that the homoepitaxial ?-Ga2O3 films on the(100)direction ?-Ga2O3 single crystal substrates have higher crystal quality and lower defect density,making it more conducive to device preparation.