碳化硅势垒机理研究及其在结型势垒二极管结构中的应用

Silicon Carbide (SiC) Schottky rectifiers have shown great value in the application of power electronics.The project presents the research work on the SiC Schottky rectifier to figure out the big issue of high turn-on voltage. Based on the research of PN junction depletion region pinch-off barrier, a new concept of Composite Barrier is proposed，which is consisted of a pinch-off barrier of PN junction depletion region and a Schottky barrier. This composite barrier structure will be fabricated by SiC material to development a brand new “SiC Composite Barrier Rectifier”. This new barrier rectifier has a great adavantage of adjustable turn-on voltage, and shows a great prospect to improve the turn-on voltage of SiC Schottky rectifiers. Meanwhile, the rectification characteristics of pinch-off barrier of PN junction depletion region are studied further to porpose a brand new “SiC Pinch-off Barrier Rectifier”. This new barrier rectifier shows great superiorities for its independence on Schottky barrier and a adjustable turn-on voltage to realize a balance of the forward conduction and reverse leakage. Based on the above research work, we may propose a set of guideline for the design of new barrier rectifier and provide a new way for the development of the next generation of SiC rectifier.

碳化硅肖特基功率二极管在电力电子变换中具有广泛的应用。目前碳化硅肖特基功率二极管存在正向开启电压较高的突出问题。针对这一问题，本项目开展PN结势垒夹断机理的研究，提出了PN结耗尽区的夹断势垒与肖特基势垒共同作用的复合势垒概念。将这一复合势垒概念用于碳化硅材料，研制出新型的碳化硅复合势垒二极管，其势垒高度可控，以大幅度改善目前碳化硅肖特基二极管开启电压特性。同时，本项目进一步研究了PN结耗尽区势垒的整流机理，提出了一种不依赖肖特基势垒的、势垒高度可控的碳化硅势垒夹断二极管新结构，以实现低开启电压、低泄露电流和零反向恢复的理想二极管特性。通过以上研究，本项目将形成一整套将PN结耗尽区势垒应用于新型碳化硅二极管研究的方法，为下一代碳化硅二极管的研发提供新的方向。

碳化硅肖特基功率二极管在电力电子变换中具有广泛的应用。目前碳化硅肖特基功率二极管存在正向开启电压较高的突出问题。针对这一问题，本项目开展PN结势垒夹断机理的研究，并基于PN结耗尽区势垒的整流机理，提出了一种不依赖肖特基势垒的、势垒高度可控的碳化硅势垒夹断二极管新结构，实现了一种可控型势垒的低开启电压、低泄露电流和零反向恢复的理想二极管特性。通过以上研究，本项目初步形成了一整套将PN结耗尽区势垒应用于新型碳化硅二极管研究的方法，为下一代碳化硅二极管的研发提供新的方向。