金属/p型SiC欧姆接触研究：势垒分布规律及其影响

Silicon carbide (SiC) is considered to be the ideal semiconductor material for high temperature, high frequency and high power applications. In production of SiC electronic devices, one of the main challenges to overcome is the fabrication of good Ohmic contacts to p-type SiC. Study the basic reason is that the Schottky barrier and distribution characteristics at metal/SiC interface which determines the electrical properties of metal/SiC contact cannot be controlled effectively. In this project, the barrier characteristics of metal contacts to p-type SiC and their effects on the formation of p-type Ohmic contact will be systematically investigated. The purpose is to develop a new barrier theory for metal contacts to p-type SiC, which will provide theoretical guidances to explore new methods in fabrication of low resistance and high reliability Ohmic contact to p-type SiC. The main research contents include: (1) Study on the improvements of the properties of p-type SiC surface. (2) Study on the barrier characteristics and their effects on the formation of Ohmic contacts experimentally. (3) Study on the current transport and barrier properties of metal/SiC theoretically. Combined with the experimental results, a barrier theory for metal contacts to p-type SiC will be developed. (4) Study on the new methods for fabricating good Ohmic contact to p-type SiC. The completion of this project may provide theoretical and experimental foundation in controlling the Schottky barrier effectively to fabricate good Ohmic contacts to p-type SiC, which would be helpful for improving the performance and reliability of SiC devices.

碳化硅(SiC)被认为是制备高温、高频、大功率器件最理想的半导体材料。然而，制备良好的p型SiC欧姆接触仍然是SiC器件研制中亟需攻克的关键技术难题，究其原因主要是决定金属/SiC接触性能的肖特基势垒无法得到有效控制。对此，本项目将对金属/p型SiC接触的势垒特性及其对p型SiC欧姆接触形成的影响进行系统研究，旨在构建金属/p型SiC接触势垒理论，获得制备低电阻高稳定的p型SiC欧姆接触的新方法。主要研究内容包括：⑴ p型SiC表面改性研究；⑵ 实验研究金属/p型SiC接触势垒分布规律及其对欧姆接触的影响；⑶ 理论研究金属/p型SiC接触的电流输运及势垒特性，并结合实验研究结果构建势垒理论；⑷ p型SiC欧姆接触新方法研究。本项目的完成，将为有效控制金属/p型SiC接触势垒，制备良好的p型SiC欧姆接触，进而提高SiC器件性能及可靠性奠定理论和实验基础。

为了突破p型SiC欧姆接触制备的技术瓶颈，项目抓住决定金属/SiC接触性能的肖特基势垒无法得到有效控制这一关键科学问题，对金属/p型SiC接触的势垒特性及其对p型SiC欧姆接触形成的影响进行了系统的研究。. 完成的主要工作如下：（1）开发了新的p型SiC表面处理技术，实现了对p型SiC表面特性的改善及有效调控；（2）通过对SiC表面特性进行调控，研究了金属、掺杂浓度以及中间绝缘层对金属/ SiC接触势垒高度及势垒不均匀分布的影响并揭示了相关机理；（3）用传递矩阵法理论研究了金属/SiC接触势垒特性，揭示了电流输运机理，构建了新的适合于金属与p型SiC半导体接触的势垒理论模型；（4）研究了p型SiC欧姆接触形成机理及理论，初步探索了制备低电阻高稳定的p型SiC欧姆接触的新思路。项目成果为有效控制金属/p型SiC接触势垒，制备良好的p型SiC欧姆接触，进而提高SiC器件性能及可靠性打下了理论和实验基础。. 在项目资助下已发表SCI论文6篇，待发表SCI论文1篇。