Trench capacitor with epi buried layer

摘要

A trench capacitor with an epi layer in the lower portion of the trench. The epi layer serves as the buried plate of the trench capacitor. A diffusion region surrounds the lower portion of the trench to enhance the dopant concentration of the epi layer. The diffusion region is formed by, for example, gas phase doping, plasma doping, or plasma immersion ion implantation.