METHODS FOR ENHANCING TRENCH CAPACITANCE AND TRENCH CAPACITOR

摘要

Methods for enhancing trench capacitance and a trench capacitor so formed are disclosed. In one embodiment a method includes forming a first portion of a trench; depositing a dielectric layer in the first portion; performing a reactive ion etching including a first stage to etch the dielectric layer and form a micro-mask on a bottom surface of the first portion of the trench and a second stage to form a second portion of the trench having a rough sidewall; depositing a node dielectric; and filling the trench with a conductor. The rough sidewall enhances trench capacitance without increasing processing complexity or cost.