InAs/GaSb超晶格红外探测器台面的ICP刻蚀研究

Study of mesa etching for InAs/GaSb superlattice infrared detector using ICP system

采用分子束外延方法在 GaSb 衬底上生长InAs/GaSb 超晶格红外薄膜材料,为获得台面结构,采用电感耦合等离子体（ICP）刻蚀技术和 Cl2/Ar 刻蚀气体,分别研究了不同刻蚀时间、不同气体比例及不同功率对 GaSb、InAs 及 InAs/GaSb 超晶格刻蚀速率和刻蚀形貌的影响。结果表明,由于刻蚀产物 InClx 的低挥发性阻挡了 Cl2的刻蚀,InAs 的刻蚀速率低于GaSb；Cl2比例在20％~40％时,刻蚀表面粗糙度最小,明显低于湿法腐蚀造成的表面损伤,有助于形成良好的欧姆接触和减小器件的表面漏电流。

InAs/GaSb superlattice infrared thin film with pin structure was grown on GaSb substrates by molecu-lar beam epitaxy system.Using inductively coupled plasma （ICP）etching technique and Cl2/Ar etching gas to form the smooth mesa,the influence of time,Cl2 percent and power on the etching rate and morphology were studied.It showed that the etching rate of InAs was lower than that of GaSb and the surface was smooth at Cl2 in the range of 20%-40%.It contributed to the formation of ohm contact and decrease surface leakage current in the photovoltaic detector.