Reduction of the Barrier Height of Silicide/p-Si1-xGex Contact for Application in an Infrared Image Sensor

Silicide/p-Si1-xGex Schottky contacts were studied for using in an infrared (IR) image sensor. Si1-xGex layers were grown on p-type (100) Si substrates by using molecular beam epitaxy (MBE). Schottky barrier heights of PtSi(Ge) or PdSi(Ge)/p-Si1-xGex contacts decreased as the Ge content increased. When the Si1-xGex layer was strained, the barrier height was smaller than when relaxed for the same value of x. These results suggest the possibility of a long wavelength (8–12 µm) IR image sensor using a silicide/p-Si1-xGex Schottky contact for the strained layer monolithically grown on a p-Si CCD substrate.