Study Of GaN Schottky Barrier Diode For Wireless Energy Transmission

With the rapid development of modern technology,wireless energy transmission has gradually become an indispensable part of people's daily life.The rectifier circuit is an important part of the wireless energy transmission system,while the rectifier diode is the most core component of the rectifier circuit.Therefore,the preparation of high-performance rectifier diodes are in great significance to wireless energy transmission.Schottky barrier diode?SBD?is based on AlGaN/GaN heterojunction can be worked at high temperature,high-power and high-frequency environment,it is very suitable as a rectifying diode in wireless energy transmission system.Although the AlGaN/GaN heterojunction Schottky barrier diode?SBD?is relatively mature,but there are still some unsolved problems,one of them is high reverse leakage current,which may cause the rectifier circuit efficiency decreased,then affect the radio output energy transmission efficiency.High isolation current in the mesa region is one of the reason for the high reverse leakage current,it is necessary to study an effective method to reduce the isolation current.Based on the preparation process of AlGaN/GaN heterojunction Schottky barrier diode?SBD?,this paper mainly studies from the perspective of mesa isolation to reduce the isolation current.The main research contents and conclusions of this paper are as follows:?1?Firstly,the leakage current of the samples was compared before and after etching,it was found that the main reason which caused the leakage current of mesa region was the isolation current on the etching surface.Then the surface before and after etching was analyzed by characterization techniques,it was found that nitrogen vacancy?V_N?defect was the main cause of surface leakage current.After that,by comparing the isolation current of the samples in different etching conditions,it was found that the isolation current of the mesa region can be effectively reduced by reducing the ICP power and RF power while the best etching conditions of ICP power was 200W and RF power was 10W.?2?Aiming at the problem that the isolation current was still high after the etching process optimized,by comparing the influence of various surface treatment methods for the isolation current of the mesa region were studied.The effects of oxygen plasma,nitrogen plasma,UV light and UV light plus hydrochloric acid for the etched surface was studied.After annealing treatment,it was found that the isolation current of the samples after annealing treatment for 120s at 400?was at the same level as the leakage current of the epitaxial material itself.The breakdown voltage of the mesa region with this condition was increased from 705V to 1775V after treatment,and the isolation current was only 1.0×10^-7A/mm at 150?.?3?Atomic force microscopy?AFM?,X-ray photoelectron spectroscopy?XPS?,photoluminescence spectroscopy?PL?and energy dispersive X-ray spectroscopy?EDX?were used to characterize and analyze the samples before and after annealing.It was found that the annealing treatment can eliminate the nitrogen vacancy defect by decomposing with the etched surface.?4?The mesa region of different substrate?Si?materials were annealing treatment and the optimal processing conditions were 300?-450?and 30s-150s.Finally,the optimized etching process and the optimal annealing process was used in the preparation process of AlGaN/GaN heterojunction Schottky barrier diode?SBD?and the reverse leakage current of the diode was measured to be only 8.3×10^-7A/mm.