Planar Type-II Superlattices (PT2SL) device

Type II InAs/GaSb strained layer superlattices represent promising material system capable of delivering more producible, large-format MWIR/LWIR focal plane arrays (FPAs). However, no viable planar processing techniques have been demonstrated for T2SL – they currently rely on mesa isolated diodes. These mesas require etching, and passivation, which complicate processing and reliability. It’s desirable to pursue planar processing technique that is compatible with T2SL. We present novel planar design called planar engineering for T2SL (PETS). The PETS consists of using different approaches including ion implantation and diffusion to create planar FPAs. We propose ion implantation process for insulation of the top p-contact to define area n-type inside the p-type contact. The ion implantation is going to define series of vertical p-n contact and generate lateral p-n junctions between each pixel. In another two approaches we propose diffusion method, to create p-type top contact on n-type wide band gap region and to generate n-type top contact on a p-type heterostructure substrate to provide nBn design. In all approaches multilayer heterojunction is proposed for photodiode configurations. The key feature for the design is planar p-on-n device, in which one or multilayer wide band gap material layer covering a narrow-band gap T2SL absorbing layer.