Xinyu Xie , Yafei Kong , Lingmao Xu , Deren Yang , Xiaodong Pi
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引用次数: 0
Abstract
Nitrogen is commonly doped to obtain n-type 4H-SiC crystals, which have been commercialized for the development of power electronics in recent years. Now the uniformity of electrical resistivity becomes an important issue for the growth of n-type 4H-SiC crystals. In this work, the effects of the radial thermal gradient and growth facet on the distribution of the electrical resistivity were investigated for a n-type 4H-SiC crystal with a diameter of 150 mm during its physical-vapor-transport growth. It is found that the resistivity at the center of the crystal is low in the early growth stage. As the crystal grows, the growth facet expands, accompanied by a reduction in the resistivity of this facet. The change in the distribution of the resistivity in the crystal is initially governed by the radial thermal gradient and then influenced by the spiral growth mode of the growth facet. In the non-facet region of the crystal step-flow growth occurs, where the doping of nitrogen is primarily affected by the temperature and C/Si ratio. In the facet region, the volume fraction of nitrogen in the mixture of argon and nitrogen input into the growth system mainly governs the doping of nitrogen during the spiral growth. The insights gained in the current work may help the fabrication of n-type 4H-SiC crystals with uniform resistivity.
氮是获得 n 型 4H-SiC 晶体的常用掺杂剂,近年来,这种晶体已商业化用于电力电子器件的开发。现在,电阻率的均匀性成为 n 型 4H-SiC 晶体生长的一个重要问题。本文研究了直径为 150 毫米的 n 型 4H-SiC 晶体在物理气相传输生长过程中径向热梯度和生长面对电阻率分布的影响。研究发现,在晶体生长初期,晶体中心的电阻率较低。随着晶体的生长,生长面扩大,该面的电阻率随之降低。晶体中电阻率分布的变化最初受径向热梯度的影响,然后受生长面螺旋生长模式的影响。在晶体的非刻面区域发生阶梯流生长,其中氮的掺杂主要受温度和碳/硅比的影响。在切面区域,输入生长系统的氩气和氮气混合物中氮气的体积分数主要决定了螺旋生长过程中氮气的掺入量。本研究获得的见解可能有助于制备具有均匀电阻率的 n 型 4H-SiC 晶体。
期刊介绍:
The journal offers a common reference and publication source for workers engaged in research on the experimental and theoretical aspects of crystal growth and its applications, e.g. in devices. Experimental and theoretical contributions are published in the following fields: theory of nucleation and growth, molecular kinetics and transport phenomena, crystallization in viscous media such as polymers and glasses; crystal growth of metals, minerals, semiconductors, superconductors, magnetics, inorganic, organic and biological substances in bulk or as thin films; molecular beam epitaxy, chemical vapor deposition, growth of III-V and II-VI and other semiconductors; characterization of single crystals by physical and chemical methods; apparatus, instrumentation and techniques for crystal growth, and purification methods; multilayer heterostructures and their characterisation with an emphasis on crystal growth and epitaxial aspects of electronic materials. A special feature of the journal is the periodic inclusion of proceedings of symposia and conferences on relevant aspects of crystal growth.