3C-SiC单晶薄膜的干法刻蚀研究

Study on dry etching of 3C SiC crystalline thin films

以四氟化碳 (CF4 )和CF4 +O2 作为刻蚀气体 ,对外延 3C SiC单晶薄膜进行了系统的等离子体刻蚀研究 .结果表明薄膜刻蚀速率在气体流量一定的情况下与O2 /CF4 流量比有关 :当O2 /CF4 流量比为 40 %左右时 ,刻蚀速率达到最大值 ;O2 /CF4 流量比低于 40 %时 ,不仅刻蚀速率降低而且还在被刻蚀样品表面形成暗表面层 ,俄歇能谱 (AES)分析表明暗层为富C表面的残余SiC ,AES分析还证实改变工艺条件可以消除富C表面 .文中还给出了经图形刻蚀后的样品的表面形貌 (SEM)

Plasma etching of cubic 3C SiC single crystal thin films produced via epitaxial growth has been systematically performed with CF 4 and CF 4+O 2 mixtures. Experimental results indicate that the etching rate of 3C SiC thin films is related to O 2/ CF 4 gas flow ratio when the total gas flow is fixed and the maxima of the etching rate are reached when O 2/ CF 4 flow ratio is about 40%. The etching rate decreases and a dark surface layer is formed as O 2/ CF 4 flow ratio decreases. Auger energy spectra (AES) analyses show that the dark layer is the residual SiC with a C rich surface. AES analyses prove that changing process conditions can eliminate a C rich surface. The SEM micrograph of a pattern etched sample is also presented.