TVS with low capacitance and forward voltage drop with depleted SCR as steering diode

US8338854B2 · kind B2 · utility

Assignee

• Alpha and Omega Semiconductor, Ltd. · US

Inventors

• Madhur Bobde · Sunnyvale, US
• Lingpeng Guan · Santa Clara, US
• Anup Bhalla · Santa Clara, US
• Limin Weng · Shanghai, CN

Key dates

• Filing date: Mar 31, 2009
• Grant date: Dec 25, 2012
• Expiry date: Nov 20, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/117

Abstract

A transient-voltage suppressing (TVS) device disposed on a semiconductor substrate of a first conductivity type. The TVS includes a buried dopant region of a second conductivity type disposed and encompassed in an epitaxial layer of the first conductivity type wherein the buried dopant region extends laterally and has an extended bottom junction area interfacing with the underlying portion of the epitaxial layer thus constituting a Zener diode for the TVS device. The TVS device further includes a region above the buried dopant region further comprising a top dopant layer of a second conductivity type and a top contact region of a second conductivity type which act in combination with the epitaxial layer and the buried dopant region to form a plurality of interfacing PN junctions constituting a SCR acting as a steering diode to function with the Zener diode for suppressing a transient voltage.