4H碳化硅单晶中的位错

4H碳化硅(4H-SiC)单晶具有禁带宽度大、载流子迁移率高、热导率高和稳定性良好等优异特性,在高功率电力电子、射频/微波电子和量子信息等领域具有广阔的应用前景。经过多年的发展,6英寸(1英寸=2.54 cm)4H-SiC单晶衬底和同质外延薄膜已得到了产业化应用。然而,4H-SiC单晶中的总位错密度仍高达10³~10⁴ cm^-2,阻碍了4H-SiC单晶潜力的充分发挥。本文介绍了4H-SiC单晶中位错的主要类型,重点讲述4H-SiC单晶生长、衬底晶圆加工以及同质外延过程中位错的产生、转变和湮灭机理,并概述4H-SiC单晶中位错的表征方法,最后讲述了位错对4H-SiC单晶衬底和外延薄膜的性质,以及4H-SiC基功率器件性质的影响。

Dislocations in 4H Silicon Carbide Single Crystals

Owing to the advantages of wide bandgap, high carrier mobility, high thermal conductivity and high stability, 4H silicon carbide (4H-SiC) has shown great potential in high-power electronics, RF/microwave electronics and quantum information. Although the industrialization of 6-inch 4H-SiC single crystals substrate and homoepitaxial films have been achieved after decades of development, the total dislocation density of 4H-SiC single crystal is still the order of magnitude of 10³~10⁴ cm^-3, which poses great challenge to the realization of the full potential of 4H-SiC. This review introduces the classification and basic properties of dislocations in 4H-SiC single crystal. The mechanism of generation, transformation and annihilation of dislocation between different types of dislocations during the growth, wafering, and the homoepitaxy of 4H-SiC single crystals are systematically reviewed. By introducing the characterization and identification of dislocations in 4H-SiC, the effect of dislocations on the properties of 4H-SiC is shown, and the device performance and reliability are also presented.