Monolithic integration technology between microlens arrays and infrared charge coupled devices

In this paper, we develop an integration technology between Si microlens and 256(H)×256(V) element PtSi Schottky-barrier infrared charge coupled device (IR-CCD) to improve the optical responsivity of CCD sensor. The refractive microlenses with the pixel size of approximately 28×28μm2 is directly fabricated on the backside of CCD substrate to focus the incident irradiation onto the active area. For the integration device the fill factor is improved by a factor of 2.1. As a result, the IR-CCD image sensors operating at 77K indicate an approximate 0.06-0.4 increase in relative optical responsivity in the spectral range of from 1 to 5μm. CCD imaging quality with microlens has been improved comparing to that without microlens to a great extent.