Improved Silicon Carbide on Silicon Crystal Quality by Epitaxial Necking

局部局限区外延的发展是为了降低硅衬底上碳化硅（SiC）薄膜的缺陷密度。假设是通过颈缩过程消除缺陷的传播，在颈缩过程中缺陷终止在SiC的侧面；颈缩后沉积的外延碳化硅应含有较少的缺陷。研究了选择性碳化硅在硅掩膜硅上的生长和非平面图案硅上的各向异性生长作为将外延限制在小区域内的方法。利用氯化烃和硅烷作为载气，探索了在低温下选择性外延生长和在不同晶体平面上增加生长各向异性的新源化学。改变窗口图案的形状和方向、源材料的氯含量、操作压力和温度，以尽量减少缺陷的传播。碳化硅是一种有吸引力的半导体，用于许多电子和光电子应用，包括高速，高功率器件，必须在高温下工作的器件，微机电传感器和太阳盲紫外线探测器。然而，这种应用受到在其他半导体上获得低缺陷碳化硅薄膜的困难的阻碍。这就是本研究要解决的问题。

ABSTRACT CTS-9319770 James Edgar Localized, confined-area epitaxy is developed to reduce the defect density of silicon-carbide (SiC) films on silicon (Si) substrates. The hypothesis is to eliminate defect propagation through the necking process, in which defects terminate on the side planes of the SiC; epitaxial silicon carbide deposited after the necking process should contain fewer defects. Both selective silicon carbide growth on silica-masked silicon and anisotropic growth on nonplanar patterned silicon are examined as methods of confining epitaxy to small areas. New source chemistries using chlorinated hydrocarbons and silanes with helium as a carrier gas are explored in attempts to selective epitaxial growth at reduced temperatures and to increase growth anisotropy on various crystal planes. The shape and orientation of the window pattern, the chlorine content of the source materials, the operating pressure, and temperature are varied to minimize the propagation of defects. Silicon carbide is an attractive semiconductor for many electronic and optoelectronic applications, including high-speed, high-power devices, devices that must operate at elevated temperatures, microelectromechanical sensors, and solar-blind ultraviolet detectors. However, such applications are hampered by the difficulty of obtaining low-defect silicon-carbide films on other semiconductors. It is this issue that is addressed in this research.