Study On The Structure And Morphology Of Gallium Oxide Thin Films Prepared By Atomization-Assisted CVD

As a third-generation semiconductor material,gallium oxide(Ga₂O₃)has a large band gap and high breakdown field strength,and has broad application prospects in gas sensors,power devices,solar-blind ultraviolet detectors,and new functional synthetic materials.Theoretically,?-Ga₂O₃has a larger band gap than?-Ga₂O₃,so high-quality?-Ga₂O₃thin films have more application value in the fabrication of semiconductor-based devices.At present,most of the existing?-Ga₂O₃thin film preparation methods have the problems of high cost and uncontrollable thin film preparation quality.In this paper,based on the new requirements of thin film preparation and growth method,a set of atomization-assisted chemical vapor deposition(AACVD)thin film preparation system is optimized.Finally,the preparation of high-quality single crystal?-Ga₂O₃thin film can be realized by using the AACVD system.To realize growing?-Ga₂O₃thin films under control,the main research contents of this paper as follows have been done:In the first part,a set of AACVD thin film preparation system is optimized.The equipment is mainly composed of atomization source,reaction chamber,exhaust gas recovery,chassis and control part.The atomization source is responsible for shattering the precursor solution into smaller-diameter aerosol particles,which are transported by the transport gas to the buffer chamber.The buffer chamber is connected with the reaction chamber and plays the role of screening the aerosol particles.The screened aerosol particles are further transported to the reaction chamber to undergo a series of reactions near the surface of the substrate and then form a film.The preparation of high-quality single-crystal?-Ga₂O₃thin films were achieved through the exploration of the preparation conditions of Ga₂O₃thin films in the early stage and the optimization of process parameters.In the second part,the regulation effect of temperature on the preparation of Ga₂O₃thin films was explored.The X-ray diffraction(XRD)test results show that from low temperature to high temperature,and then to higher temperature,the Ga₂O₃film has changed from amorphous to?-Ga₂O₃single crystal,and then to?-Ga₂O₃,?-Ga₂O₃two-phase mixed polycrystalline The phase transition of Ga₂O₃is realized,and the control of the phase transition of Ga₂O₃with temperature change is realized,and the suitable temperature range for the preparation of?-Ga₂O₃thin films should be between 475°C and550°C.Atomic force microscopy(AFM)morphology characterization results show that with the increase of the preparation temperature of Ga₂O₃thin films,the grain size of Ga₂O₃thin films increases,while the surface root mean square roughness(RMS)of Ga₂O₃thin films increases first and then decreases The trend of increasing again,its value decreased from 23.5 nm to 22.7 nm and then increased to 24.8 nm,and with the increase of temperature,the growth mode of Ga₂O₃film changed.In the third part,the regulation effect of the pressure difference on the preparation of Ga₂O₃thin films was explored.Three Ga₂O₃thin film preparation temperature conditions of 475°C,500°C and 525°C were selected,and five groups of isobaric gradient thin film preparation experiments were set from 5 to 25 Pa at intervals of 5 Pa.According to the analysis of XRD characterization results,the pressure difference has an important influence on the crystal quality of Ga₂O₃films.At the same time,the results AFM morphology characterization show that different preparation pressure differences have different effects on the surface morphology of Ga₂O₃films.In the fourth part,the single crystal properties of the single crystal?-Ga₂O₃thin film samples were explored.The single crystal?-Ga₂O₃thin film sample with the smallest value of?-Ga₂O₃(0006)crystal orientation diffraction peak obtained by software analysis was selected for high-resolution X-ray diffraction rocking curve test.The results show that the prepared Ga₂O₃thin film samples are high-quality single crystal?-Ga₂O₃thin film samples,and the diffraction peak width at half maximum of the?-Ga₂O₃(0006)crystal orientation is only 0.053°(190.8 arcsec).