Study Of 650V Vertical Superjunction MOSFET

As well know,the specific on-resistance of traditional MOSFET is approximately proportional to the 2.5th power of breakdown voltage,which limits the further improvement of device performance.The super junction MOSFET is based on drift regions with PNPN structure alternately.By keeping the charge balance between the P column and the N column,the whole drift region can be completely exhausted and withstand higher breakdown voltage.Therefore,the super-junction MOSFET can break through the "silicon limit" of traditional MOSFET,by reducing the on resistance significantly and improving the conversion efficiency,which has important and wide application in the field of high voltage and high power system.In this paper,both the theoretical and experimental research have been performed aiming at the 650 V vertical super junction MOSFET.Typical samples were fabricated,based on which the electrical performance test,reliability evaluation and system-level application verification are carried out.The main research results and work are in the following.(1)The theoretical model of vertical super-junction MOSFET is established with Silvaco software.The effect of the multiple epitaxial processes,trench etching and filling processes,gate oxygen thickness and P-body implantation dose on the MOSFET characteristics is studied by means of simulations.And the temperature characteristics of the super-junction MOSFET are also conducted.Valuable and practical results and laws are achieved,which paves the way for the device design and manufacture.(2)Based on the commercial standard process,the fabrication,electrical testing and reliability of super-junction MOSFET are performed.The results,obtaining from 132 randomly selected samples,show a good consistency in the threshold voltage,breakdown voltage,on-resistance and leakage current at 650 V reverse voltage,which meets the design specifications.In addition,randomly sampled 100 super-junction MOSFET devices are divided into 5 groups on average,in which the PCT test,TC test,HTRB test,HTGB test and PC test are conducted,respectively.The result shows there is no failure and the manufactured super-junction MOSFET have a good reliability.(3)The system-level application of the fabricated super-junction MOSFET in 15 kW charging pile module is verified.The result shows all the devices meet the technical specifications in the condition of the test of voltage stress,current stress and temperature stress.And the charging pile module works well under the limit conditions.