4H-SiC结势垒肖特基二极管制备及常温离子注入研究

发布时间：2018-04-27 20:48

  本文选题：碳化硅 + 肖特基二极管　； 参考：《南京理工大学》2017年硕士论文

【摘要】：作为第三代半导体材料的代表,SiC单晶具有禁带宽度大、饱和电子漂移速率大、临界击穿场强高和热导率高等优势,可以用于制备耐高温、散热好、耐高压、高频大功率器件。目前,SiC单晶已经被广泛应用于肖特基二极管(SBD)、pin二极管以及结势垒肖特基二极管(JBS)等功率器件的制备。在这些功率器件中,SiC JBS二极管具有SBD二极管和pin管两者的优势,一直是研究的热点之一。目前SiC JBS二极管研究主要集中在离子注入和结终端技术方面。本文基于模拟的方法,研究了 n型4H-SiC材料中A1注入结深、浓度分布与注入角度、缓冲层、能量和剂量的关系,优化了注入深度500nm,浓度均匀分布的注入条件,并进行了常温注入实验。注入完成后,进一步探讨了保护方式、温度等对SiC晶圆激活效果,注入条件和退火保护方式对SiC表面粗糙度的影响。在激活完成后,在材料上生长了一层Ni并进行退火,分析了激活浓度对Ni与A1注入形成的p-SiC的欧姆接触的影响。实验结果表明以4°偏角注入,用100nmSiO_2作为缓冲层进行注入,以1750℃用SiC上下夹片保护进行退火,可以得到表面粗糙度为0.862nm,激活浓度为4.25×1019 cm-3的p-SiC。1050℃-2min的欧姆接触退火条件为最优条件,制备出比接触电阻率为4.10mΩ.cm2的欧姆接触。轻微的过刻蚀有利于提高肖特基接触性能。同时通过对场板长度的优化,对场限环参数的模拟结合离子注入制备出了开启电压在1V、击穿电压1300V、理想因子1.49、势垒高度1.07eV的SiCJBS器件。
[Abstract]:As the representative of the third generation semiconductor material, sic single crystal has the advantages of wide band gap, high saturated electron drift rate, high critical breakdown field strength and high thermal conductivity. It can be used to fabricate high-temperature, heat-dissipation, high-voltage and high-frequency high-power devices. At present, sic single crystal has been widely used in the fabrication of Schottky diode (SBD) pin diode and junction barrier Schottky diode (JBS). Among these power devices, sic JBS diodes have the advantages of both SBD diodes and pin diodes. At present, the research of SiC JBS diode is mainly focused on ion implantation and junction terminal technology. Based on the simulation method, the relationship between Al implantation depth, concentration distribution and implantation angle, buffer layer, energy and dose in n-type 4H-SiC is studied. The implantation conditions of 500 nm implantation depth and uniform concentration distribution are optimized. The experiment of injection at room temperature was carried out. After the injection, the effects of protection, temperature and so on on the activation of SiC wafer, the effect of injection conditions and annealing protection on the surface roughness of SiC were discussed. After activation, a layer of Ni was grown on the material and annealed. The effect of activation concentration on ohmic contact of p-SiC implanted with A1 was analyzed. The experimental results show that 4 掳angle is injected, 100nmSiO_2 is used as buffer layer, and SiC upper and lower clamps are used for annealing at 1750 鈩，

本文编号：1812294