Inductively coupled plasma etching and processing techniques for type-II InAs/GaSb superlattices infrared detectors toward high fill factor focal plane arrays
Inductively coupled plasma etching and processing techniques for type-II InAs/GaSb superlattices infrared detectors toward high fill factor focal plane arrays
复制标题
DOI：
10.1117/12.810030
复制
发表时间：
2009-01
期刊：
影响因子：
--
通讯作者：
E. Huang;B. Nguyen;D. Hoffman;P. Delaunay;M. Razeghi
中科院分区：
文献类型：
--
作者：
E. Huang;B. Nguyen;D. Hoffman;P. Delaunay;M. Razeghi
II型InAs/GaSb超晶格（T2 SL）光电探测器的挑战是实现第三代焦平面阵列（FPA）的高填充因子、高纵横比蚀刻。首先，我们比较了BCl 3/Ar电感耦合等离子体（ICP）和电子回旋共振（ECR）干法刻蚀后的单元素T2 SL光电二极管的形态和电学结果。采用Si 3 N4硬掩模，ICP刻蚀的结构具有更高的侧壁垂直度和光滑度，这对于实现高填充因子FPA至关重要。采用SiO2钝化的ICP刻蚀单元件器件截止波长为9.3μm，垂直侧壁深度为7.7μm，零偏压下的电阻面积积大于1，000 Ω cm 2，77 K下的最大微分电阻超过10，000 Ω cm 2。通过仅修改在制造步骤中的蚀刻技术，ICP蚀刻的光电二极管显示出一个数量级的减少，在其暗电流密度相比，ECR蚀刻的设备。最后，在具有11μm深的3μ m宽沟槽的多元件阵列上演示了高深宽比刻蚀。
A challenge for type-II InAs/GaSb superlattice (T2SL) photodetectors is to achieve high fill factor, high aspect ratio etching for third generation focal plane arrays (FPAs). Initially, we compare the morphological and electrical results of single element T2SL photodiodes after BCl3/Ar inductively coupled plasma (ICP) and electron cyclotron resonance (ECR) dry etching. Using a Si3N4 hard mask, ICP-etched structures exemplify greater sidewall verticality and smoothness, which are essential toward the realization of high fill factor FPAs. ICP-etched single element devices with SiO2 passivation that are 9.3μm in cutoff wavelength achieved vertical sidewalls of 7.7μm in depth with a resistance area product at zero bias of greater than 1,000 Ωcm2 and maximum differential resistance in excess of 10,000 Ωcm2 at 77K. By only modifying the etching technique in the fabrication steps, the ICP-etched photodiodes showed an order of magnitude decrease in their dark current densities in comparison to the ECR-etched devices. Finally, high aspect ratio etching is demonstrated on mutli-element arrays with 3μm-wide trenches that are 11μm deep.