Patent ID: 6812094
Filing Date: 2004-11-02
Classification: H01L

Abstract:
A method for fabricating a trench capacitor with an increased capacitance due to roughening a surface of a semiconductor within a trench, which comprises:providing a semiconductor substrate having a surface; placing the semiconductor substrate in a furnace; introducing a process gas into the furnace, the process gas including oxygen and an inert gas selected from the group consisting of argon and nitrogen; maintaining an oxygen concentration below approximately 10% in the furnace; forming mesopores with a diameter between approximately 10 nm and approximately 50 nm in the surface of the semiconductor substrate by annealing the substrate at a temperature between approximately 950Â° C. and approximately 1200Â° C.; smoothening the mesopores by etching the substrate in a solution containing water, ammonium hydroxide, and hydrogen peroxide; disposing a dielectric layer on the semiconductor substrate; disposing a first electrode on said dielectric layer; and forming a second electrode in said semiconductor substrate adjunct to said dielectric layer.