Bottle-shaped trench capacitor with enhanced capacitance

US8021945B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Xi Li · Somers, US
• Russell H. Arndt · Fishkill, US
• Kangguo Cheng · Schenectady, US
• Richard O. Henry · Newburgh, US
• Jinghong Li · Poughquag, US

Key dates

• Filing date: Apr 14, 2009
• Grant date: Sep 20, 2011
• Expiry date: Nov 26, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S438/964

Abstract

In accordance with an aspect of the invention, a method is provided for fabricating a semiconductor chip including a trench capacitor. In such method, a monocrystalline semiconductor region can be etched in a vertical direction through an opening in a dielectric layer to form a trench exposing a rough surface of monocrystalline semiconductor material. The trench has an initial lateral dimension in a first direction transverse to the vertical direction. The semiconductor material exposed at the surface of the trench then is etched in a crystallographic orientation-dependent manner to expose a multiplicity of crystal facets of the semiconductor material at the trench surface. A dopant-containing liner may then be deposited to line the surface of the trench and a temperature of the substrate then be elevated to drive a dopant from the dopant-containing liner into the semiconductor region adjacent to the surface. During such step, typically a portion of the semiconductor material exposed at the wall is oxidized. At least some of the oxidized portion is removed to expose a wall of an enlarged trench, along which wall a dielectric layer and conductive material are formed in order to form…