Patent ID: 7041553
Filing Date: 2006-05-09
Classification: H01L

Abstract:
1. A method of making a buried plate region in a semiconductor substrate, comprising: forming a trench in a semiconductor substrate, the trench having a trench sidewall, the trench sidewall including an upper portion, and a lower portion disposed below the upper portion; forming a liner along at least the lower portion of the trench sidewall; thereafter forming a dopant source layer overlying the liner, the dopant source layer not being disposed along the upper portion of the trench sidewall; and annealing the semiconductor substrate to drive a dopant from the dopant source layer through the liner into the semiconductor substrate adjacent to the lower portion of the trench sidewall while preventing the dopant from being driven into the semiconductor substrate adjacent to the upper portion of the trench sidewall, wherein the liner functions as a diffusion barrier inhibiting diffusion of at least one of oxygen or the dopant into the semiconductor substrate during the step of forming the dopant source layer, and permits the dopant to diffuse through the liner into the semiconductor substrate during the step of annealing to form the buried plate.