InAs/GaSb超晶格探测器台面工艺研究

InAs/GaSb SLs探测器台面刻蚀常用的工艺有干法刻蚀和湿法刻蚀.研究了三种等离子刻蚀气体(Cl2基, Ar基和CH4基)对超晶格的刻蚀效果,SEM结果表明,CH4基组分能够得到更加平整的表面形貌和更少的腐蚀坑;之后采用湿法腐蚀工艺,用于消除干法刻蚀带来的刻蚀损伤,分别研究了酒石酸系和磷酸系两种腐蚀溶液的去损伤效果,结果表明,磷酸系腐蚀液的去损伤效果更好,且腐蚀速率更加稳定.采用优化的台面工艺制备了InAs/GaSb SLs探测器,其I-V特性曲线表明二极管具有较低的暗电流,其77 K时动态阻抗R0A =1.98104 cm2.

Mesa etching process for InAs/GaSb SLs grown by MBE

Dry etching and wet etching were usually used in the mesa etching process of InAs/GaSb SLs. Three kinds of etch atmosphere(Cl2 based, Ar based and CH4 based)were studied in inductively coupled plasma(ICP) dry etching. The results show that the CH4 based atmosphere give much more smooth surface and less etch pits according to the SEM measurement. Then wet etching was introduced to eliminate the etching damage of ICP dry etching, tartaric acid based etchant and phosphoric acid based etchant, were studied. It was found that the phosphoric acid based etchant gave better result to remove etching damage, and provide a more stable etching rate. InAs/GaSb SLs photodiodes by standard photolithographic procedures were fabricated using this etching recipe. The diodes exhibits a high breakdown voltage and low leakage current, the measurement result reveals a dynamic impedance values of R0A =1.98104 cm2 at 77 K.