| Abstract: | A method is provided for fabricating a backside-illuminated photodetector
in which a device wafer is joined to a readout wafer in an IC
hybridization step. Before the IC hybridization step, the device layer is
defined in the device wafer, and an LPCVD layer is formed over the device
layer. The LPCVD layer may be a passivation layer, an antireflection
coating, or both. The side of the device wafer having the LPCVD layer is
bonded to a handle wafer, the IC is hybridized by mating the device wafer
to the readout wafer, and the handle wafer is then removed, exposing the
LPCVD layer. Because the LPCVD layer is formed before the active devices
are fabricated, it can be made by high-temperature techniques for
deposition and processing. Accordingly, a layer of high quality can be
fabricated without any hazard to the active devices. |