Optical sensitivity non-uniformity analysis and optimization of a tilt optical readout focal plane array

An optical readout focal plane array (FPA) usually has a differently tilted reflector/absorber at the initial state due to the micromachining technique. The angular deviation of the reflector/absorber has a strong impact on the optical sensitivity non-uniformity, which is a key factor which affects the imaging uniformity. In this study, a theoretical analysis has been developed, and it is found that the stress matching in SiO2-Aluminum (Al) bilayer leg could make a contribution towards reducing the optical sensitivity non-uniformity. Ion implantation of phosphorus (P) has been utilized to control the stress in SiO2 film. By controlling the implantation energy and dose, the stress and stress stability are modified. The optical readout FPA has been successfully fabricated with the stress-control technique based on P+ implantation. It is demonstrated that the gray response non-uniformity of optical readout FPA has decreased from 25.69% to 10.7%.