InAs/GaSb 제2형 응력초격자(SLS)를 활성층에 탑재한 [$320{ imes}256$] 초점면 배열(FPA) 적외선 열영상 모듈을 제작하고 열영상을 구현하였다. p-i-n형으로 설계된 소자의 활성층(i) 구조는 300 주기의 [13/7]-ML [InAs/GaSb]-SLS로 구성되어 있고, p와 n 전극층에는 각각 60주기의 [InAs:Be/GaSb]-SLS와 115 주기의 [InAs:Si/GaSb]-SLS 구조를 채용하였다. 시험소자의 광반응(PR) 스펙트럼으로부터 피크 파장(${lambda}_p$)과 차단 파장(${lambda}_{co}$)은 각각 ${sim}3.1/2.7{mu}m$과 ${sim}3.8{mu}m$이고 180 K 온도까지 동작을 확인하였다. 단위 화소의 간격/메사는 $30/24{mu}m$ 규격으로 설계되었으며, [$320{ imes}256$]-FPA는 표준 광묘화법으로 제작하였다. $18/10{mu}m$의 In-bump/UBM 공정과 flip-chip 결합 기술을 적용하여 FPA-ROIC 열영상 모듈을 완성하였으며, 중적외선용 영상구동 회로 및 S/W를 활용하여 열영상을 시연하였다.
An infrared thermographic imaging module of [$320{ imes}256$] focal-plane array (FPA) based on [InAs/GaSb] strained-layer superlattice (SLS) was fabricated, and its images were demonstrated. The p-i-n device consisted of an active layer (i) of 300-period [13/7]-ML [InAs/GaSb]-SLS and a pair of p/n-electrodes of (60/115)-period [InAs:(Be/Si)/GaSb]-SLS. FTIR photoresponse spectra taken from a test device revealed that the peak wavelength (${lambda}_p$) and the cutoff wavelength (${lambda}_{co}$) were approximately $3.1/2.7{mu}m$ and $3.8{mu}m$, respectively, and it was confirmed that the device was operated up to a temperature of 180 K. The $30/24-{mu}m$ design rule was applied to single pixel pitch/mesa, and a standard photolithography was introduced for [$320{ imes}256$]-FPA fabrication. An FPA-ROIC thermographic module was accomplished by using a $18/10-{mu}m$ In-bump/UBM process and a flip-chip bonding technique, and the thermographic image was demonstrated by utilizing a mid-infrared camera and an image processor.
