Mfg. semiconductor element with differently doped layers - by wafer silicon@ bonding and wafer thinning

摘要

In the prodn. of semiconductor elements with differently doped layers, in which two or more doped silicon wafers are joined by silicon bonding, the novelty is that the thickness of at least one of the wafers is reduced by machining (esp. grinding or chemical machining) after silicon bonding and that at least one of the wafers has heavy doping. The dopant distribution in the wafers can be modified in the wafers by a diffusion process and, subsequently, the charge carrier lifetime can be increased by a gettering process. The heavily doped wafer may be used as dopant source for the other wafer(s) in the diffusion operation. ADVANTAGE - The semiconductor elements can be produced without lengthy deep diffusion operations and the risk of wafer fracture is much reduced so that larger wafer diameters can be used.