InAs/GaSb Ⅱ类超晶格材料台面腐蚀

Mesa etching of typeⅡ InAs/GaSb superlattice

研究了InAs/GaSbⅡ类超晶格的几种台面腐蚀方法.实验所用的InAs/GaSbⅡ类超晶格材料是使用分子束外延设备生长的,材料采用PIN结构,单层结构为8 ML InAs/8 ML GaSb.腐蚀方法分为干法刻蚀和湿法腐蚀两大类.干法刻蚀使用不同的刻蚀气氛,包括甲基、氯基和氩气;湿法化学腐蚀采用了磷酸系和酒石酸酸系的腐蚀液.腐蚀后的材料台阶高度是使用α台阶仪测量,表面形貌通过晶相显微镜和扫描电镜表征.经过对比研究认为,干法刻蚀中甲基气氛刻蚀后的台面平整,侧壁光滑,侧壁角度为约80度,台阶深度易控制,适合深台阶材料制作.湿法腐蚀中磷酸系腐蚀效果好,台面平整,下切小,表面无残留,适用于焦平面红外器件制作工艺.

Several etching methods for mesa of InAs/GaSb superlattice in IR FPA were investigated. The InAs/GaSb su- perlattices used here were prepared by molecular beam epitaxy. A standard PIN device structure was applied in all sam- pies with a period of 8 ML InAs/8 ML GaSb. Inductively coupled plasma etching with CH4, C12 and Ar as reactive ga- ses and wet etching with solution including orthophosphoric acid and tartaric acid were compared. The mesa height was measured by a-step meter system, while surface morphology was evaluated by microscope and scanning electron micros- copy. The results shows that CH4 based etching can give a smooth surface and slippery lateral with an 80 degree angle. Furthermore, the mesa depth was easy to control. This method is suitable for fabricating deep mesa device. It has also been found that etching with the solution based on orthophosphoric acid can obtain a smoother, clear surface and low in the longitudinal. It is a better way to fabricate IR FPA.