Research On GaV-on-Si Super-Barrier Diode

After nearly a decade of rapid development,GaN devices have shown increasingly significant performance advantages in high-speed,high-efficiency,high-power applications compared to traditional silicon-based MOSFETs.In order to make full use of the unique advantages of GaN devices,such as high frequency,high energy efficiency,high power density and high operating temperature,and to maximize the performance of GaN-based power electronic systems,it is an inevitable trend to develop single-chip silicon-based GaN power ICs.Except for GaN transistors,diodes are also one of the core components for the development of GaN monolithic power ICs.However,the industry has little research on GaN-on-Si diodes,and there are no commercial products at present.Therefore,it is necessary to develop a GaN power diode with ultra-low turn-on voltage,low on-resistance,low reverse leakage,high withstand voltage and high uniformity.In view of the above background,a novel high performance GaN-on-Si diode structure is proposed and its application in the direction of RF mixed signal is studied.The main contents are as follows:?1?A novel Recess-free hybrid GaN lateral power diode?Hybrid-anode Super-barrier Diode-HSD?is proposed.By using a super-thin barrier AlGaN/GaN heterojunction,and the channel 2DEG density of the HSD structure(¹0¹² cm^-2)is one order of magnitude lower than the conventional barrier(¹0¹³ cm^-2),and making it have natural rectifying characteristics.Later,by growing a dielectric layer such as LPCVD-SiNx on the heterojunction,the dielectric charge and dielectric stress introduced by it are used to restore 2DEG in the access region,and the under-gate region retains its natural rectifying characteristics due to the removal of the dielectric layer.Therefore,the on-resistance of the device can be sufficiently reduced while achieving rectification characteristics.Compared with the conventional barrier structure,HSD has two major advantages:First,the precise regulation of the turn-on voltage can be achieved by controlling the thickness of the heterojunction barrier layer grown by MOCVD;Second,there is no need for additional Schottky barrier“treatment”,such as etching or ion implantation,which can greatly reduce the lattice damage that may occur in the process and the device performance degradation caused by it.Therefore,it is beneficial to achieve high performance GaN diodes.?2?The simulation design optimizes and experimentally prepares a GaN HSD device.In this paper,the thickness of the heterojunction barrier layer is firstly optimized by simulation.Secondly,the optimized HSD is subjected to the flow film experiment,and the process menu is continuously optimized in the experiment to develop the preparation technology suitable for the HSD device.Finally,the turn-on voltage of the HSD device is only 0.35V,and the breakdown voltage is more than 800V when Lac=10?m.The small turn-on voltage standard deviation of the 155 devices fabricated on the same wafer is only0.05V,indicating high device uniformity.?3?Extended application of HSD devices-zero bias RF mixers,which is connected in parallel by two GaN HSD devices.The prepared mixer has strong nonlinearity near 0V,and the turn-on voltage at room temperature is only 0.2V.It can be seen from the preliminary RF test results that the device exhibits good mixing characteristics when the temperature is as high as 200°C,indicating that the device has excellent temperature characteristics.