SEMICONDUCTOR DEVICE AND METHOD OF FORMING THEREOF

A system and a method are disclosed for forming a bottle-neck shaped backside contact structure in a semiconductor device, wherein the bottle-neck shaped backside contact structure has a first side partially within the first source/drain structure, a second side contacting a backside power rail, and a liner extending from the first side to the backside power rail. The liner includes a first region comprised of either a Ta silicide liner or a Ti silicide liner, a second region comprised of a Ti/TiN liner and a third region comprised of either a Ta silicide liner or a Ti silicide liner. The backside contact structure includes a first portion having a positive slope and a second portion, adjacent to the first portion, having no slope.