硅基外延β-SiC薄膜在不同刻蚀气体中的等离子体刻蚀研究

Study on Plasma Etching of β-Sic Thin Films Prepared by Epitaxial Grown on Si-Substrates in Different Etching Gases

用等离子体刻蚀（ＰＥ）工艺，以四氟化碳（ＣＦ４）和六氟化硫（ＳＦ６）以及它们与氧气（Ｏ２）的混合气体作为刻蚀气体分别对Ｓｉ基外延生长的β－ＳｉＣ单晶薄膜进行了刻蚀工艺研究。结果表明在同样刻蚀工艺条件下，以ＳＦ６＋Ｏ２作为刻蚀气体要比以ＣＦ４＋Ｏ２作为刻蚀气体具有更高的刻蚀速率；在任何气体混合比条件下经 ＳＦ６＋Ｏ２ 刻蚀后的样品表面都不会产生富碳（Ｃ）表面的残余ＳｉＣ层；而经ＣＦ４＋Ｏ２刻蚀后的样品表面是否产生富Ｃ表面残余ＳｉＣ层则与气体混合比条件有关，但刻蚀后的样品表面更为细腻。文中还对不同刻蚀气体下的刻蚀产物进行了讨论比较。

Plasma etching of β-SiC single crystal thin films produced via epitaxial growth on Si-substrates was performed with different etching gases such as CF4, Sf6, CF4+O2 and SF6+O2 mixtures. Experimental results indicate that when SF6+O2 mixture is used as etching gas, the etching rates of β-SiC films are higher than those when CF4+O2 is used as reactant gas. When SiC films are etched by using SF6+O2 mixture, no dark layer which is residual SiC with a C-rich surface is formed under any gas mixing ratio used. However, there is a very slight discoloration in the sample surface when SiC is etched by using CF4+O2 mixture, which indicates that the sample surface being etched has a better smooth finish. Etching products using different etching gases are also compared and discussed.