离子束刻蚀碲镉汞的沟槽深宽比改进

Improving the aspect ratio of ion beam etched trenches in HgCdTe

高深宽比离子束刻蚀技术是实现碲镉汞红外焦平面探测器的关键工艺技术.国内应用最广泛的双栅考夫曼刻蚀机束散角较大,沟槽深宽比较低.针对Ar离子束刻蚀机,尝试了三种提高深宽比的方法:选择不同的光刻胶做掩模、改变刻蚀角度和使用三栅离子源,并通过扫描电子显微镜(SEM)观察了碲镉汞刻蚀图形的剖面轮廓并计算了深宽比.分析了这些工艺方法对刻蚀图形轮廓的影响,获得了一些有助于获得高深宽比的离子束刻蚀沟槽的实验结果.

The aspect ratio of trenches is one of the key parameters in processing the Hg Cd Te infrared focal plane arrays( IRFPAS). The divergence angle of the two-grid Kaufman ion-beam source that is widely used in China at present is typically large. Using such an ion beam source,the aspect ratio of Hg Cd Te isolation trenches is comparatively low. Several methods were employed in the etching process to increase the aspect ratio of trenches etched by Ar+ion beam apparatus,such as with different types of photoresists,changing the incidence angle of ion beam,and utilizing three-grid Kaufman ion-beam source. The cross-section profile of the trenches on Hg Cd Te arrays was studied with scanning electron microscope( SEM) and the aspect ratio was calculated. The influences of these methods on etching profiles were given and many results desirable for the design of high aspect ratio of ion beam etched trenches were achieved.