Research On The Process Of SiC SBD And Utilize Silvaco To Simulate Its Characteristic

Following the development of the first generation Si semiconductor and the second generation compound semiconductor, SiC semiconductor material is the third generation wide band semiconductor material. Wide band semiconductor refers to these whose energy gap wider than the 2.6 eV, all the outstanding physical and electrical properties, wide band gaps, high heat conductivity, big saturated drifting velocity and high critical breakdown electric field, and other unique advantages, make SiC to be the ideal semiconductor material which can be applied in the area of high power, high frequency, endurable of high temperature, radio resistant..As the metal semiconductor rectifier junction, Schottky barrier diode is a high-speed switch power rectifier, which is the basic device in high frequency electronics and power circuit microwave field. As a single polarity majority device, it can neglect minority storage effect, so it has excellent frequency characteristics, it has low on resistance, low consumption and almost without diffusion capacitance, These features decided its application in high frequency and high power rectifier.since the reverse breakdown voltage of the conventional silicon schottky diodes lower than 100V, and they can't work suitably above 150℃, but SiC SBD combined higher voltage rapid, lower power loss and endurable of high temperature together to make up for the shortage of conventional SBD, make itself to be an ideal device. Theory suggests that these SiC SBD with low threshold voltage, breakdown voltage more than 5kV, and can work above 600℃. High levels of multiple types of SiC device have been developed all over the world successively, but most of them are still in laboratory research phase. The development of SiC device in domestic started later and we have a long way to catch up with foreign countries. One of the critical crafts which have effect on the SiC material application in high temperature, high-power, and high frequency is to prepare the ohm contact with high stability and low resistance. The quality of Ohm contact and value of the contact resistance directly affect the performance indicators, such as the device efficiency, gain and the switch speed.This paper started from the actually research sense, discussed the SiC properties and process, combined the contact theory of metal and semiconductor, put forward the improved manufacturing process: first, we utilized Ni silicide to optimize the ohm contact, and we learned from theory that the specific contact resistance of Ti/Ni-n SiC is smaller; second, we researched a lot in terminal junction, we introduced P+ ring to increase the breakdown voltage which increase the radius of the edge of the depletion that will reduce the margin electrical field, sometimes we can also introduce the second or third ring to achieve better result. Third, we can introduce the super junction to balance the contradiction between breakdown voltage and forward conduct characteristic, the most obvious feature of SJ is to reduce the on resistance, and we can also improve the blocking-up property, the theory of SJ will be introduced in detail in chapter 4; at the end of this paper, we utilized Silvaco-TCAD to simulate 4H-SiC SBD, the result of the simulation including two aspects: craft structure and forward characteristic, we set the process condition according to the expected forward conduct voltage, and compile the simulation program code to obtain the parameters that we need, we also introduced p+ ground ring to improve reverse breakdown property.We have been instructed from the design above, combined the working experience in the production line of 47th institute of China electronics technology group to complicate this paper, I start from rectifier theory and schottky theory, simultaneously we utilized Silvaco software to launch structure simulation and positive characteristic simulation research of high-power 4H - SiC SBD device. My mainly aim is to reduce the ON-resistance and improve reverse breakdown voltage, we have analyzed the procession improvement from theory through introducing the p+ ground ring and super junction, and then We optimized the parameters and the procession to maintain the required breakdown voltage, to reduce the on resistance, to maximize the output power.