Improved Silicon Carbide on Silicon Crystal Quality by Epitaxial Necking

为了降低硅衬底上碳化硅薄膜的缺陷密度，研制了CTS-9319770詹姆斯-埃德加局域有限区域外延技术。假设是通过缩颈过程消除缺陷扩展，在缩颈过程中，缺陷终止于碳化硅的侧面；缩颈过程后沉积的外延碳化硅应该包含较少的缺陷。研究了在二氧化硅掩膜硅上选择性生长碳化硅和在非平面图形硅上的各向异性生长作为将外延限制在较小区域的方法。探索了使用氯代烃和硅烷、氦作为载气的新的源化学，试图在更低的温度下选择外延生长，并在不同的晶面上增加生长的各向异性。窗口图案的形状和取向、源材料的氯含量、操作压力和温度都是可变的，以最大限度地减少缺陷的传播。碳化硅是一种极具吸引力的半导体，可用于许多电子和光电子应用，包括高速、大功率器件、必须在高温下工作的器件、微型机电传感器和日盲紫外线探测器。然而，由于在其他半导体上很难获得低缺陷的碳化硅薄膜，这类应用受到了阻碍。本研究就是针对这一问题展开的。

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.