Critical Technology Of AlGaN/GaN Switching Device

AlGaN/GaN Schottky barrier diode(SBD) and High Electron Mobility Transistor(HEMT), with high voltage, low conduction resistance, high switching frequency, high system efficiency, high thermostability, anti-radiation and other advantages has become the important research object in the microwave and radiofrequency, power electronics and other fields. In this paper, We mainly studies the influence of critical process conditions on the device performance during the fabrication of Al Ga N / Ga N SBD and HEMT devices, and then test and analyze the device on the basis of the optimized process parameters. This paper is supported by 863 Project(number 2015AA033305), the main study contents are as follows:1. Prepare the Hall test samples, and the experimental epitaxial wafers are measured by Hall effect measurements for characteristic parameters; Analyze and optimize the wet chemical etching conditions for epitaxial wafers, and the epitaxial wafers are etched under the optimized conditions. The dislocation density was obtained by counting the etch pits with different diameter, and then the quality of the epitaxial wafer is evaluated.2. Critical process steps for the AlGaN/GaN SBD device are optimized by single-step test. To solve the appeared paste rubber and rough degrees problem during etching active region mesa by ICP, this paper proposes to improve the distribution of the mask conditions and combine different ICP etch speeds, effectively alleviating the mask membrane needs and surface morphology problem; In the preparation process of ohmic electrode, the effect of the annealing temperature and annealing time on contact characteristics of AlGaN/GaN ohmic electrode is analyzed, and improve the annealing conditions of Ti / Al / Ni / Au ohmic contact. Study the effect of the annealing temperature on the saturated characteristics of the devices; Compare the contact characteristics between the recessed structure and the conventional structure Schottky electrodes, testing and analyzing the differences of DC characteristics with different Al Ga N / Ga N SBD structure.3. Design AlGaN/GaN SBD device layouts with different electrode size, electrode spacing, terminal protection and single-finger structure, and the devices are prepared combined with the optimized process parameters, after which test and analyze the devices. On the research and analysis of the conduction characteristics of the device, structural design and process conditions are optimized to improve the device properties.4. Nano-gate Al Ga N / Ga N HEMT devices are studied, and design the layout of different device structure, improving the problems appeared in manufacturing process. The difference of the conduction characteristics between the source and the drain in devices with different structure have been tested and analyzed.