High-voltage integrated vertical resistor and manufacturing process thereof

US7053463B2 · kind B2 · utility

Assignee

• STMicroelectronics SA

Inventor

• Davide Giuseppe Patti · Mascalucia, IT

Key dates

• Filing date: Jan 12, 2004
• Grant date: May 30, 2006
• Expiry date: Jan 12, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/615

Abstract

The manufacturing process comprises the steps of growing epitaxially a first layer from a semiconductor material substrate, forming in the first layer a first and a second buried region spaced from one another and having conductivity of the type opposite that of the first layer; growing epitaxially on the first layer a second layer of semiconductor material having the same type of conductivity as the first layer; forming in the second layer a trench extending in depth beyond the buried regions, arranged between the buried regions, and having, in plan view, a frame shape; forming an oxide layer covering the lateral walls and the base wall of the trench; and filling the remaining part of the trench with an isolating material. By this means, the portion of the second layer surrounded by the trench defines a first high-voltage resistor having a vertical structure and current flow, whereas the portion of the first layer arranged below the trench defines a second high-voltage resistor arranged in series with the first high-voltage resistor, and also having a vertical structure and current flow.