Plasma etching of polycrystalline silicon films using chlorine based mixtures for fabrication of infrared sensors and MOS gates

Image sensors based on active pixel sensor (APS) and fabricated employing a simple MOS technology are used in a fast growing number of applications. Large feature size is used to offer high photodetection sensitivity and low cost. This kind of sensors became very popular since the beginning of 90's. Here, for devices fabrication, plasma etching of Si with chlorine containing gas mixtures is employed which provides anisotropic etch with vertical walls, high uniformity and well controlled etch rate.