Patent ID: 9337178
Filing Date: 2016-05-10
CPC Classification: H01L

Claim Text:
1. A method of forming an ESD device comprising: providing a semiconductor substrate of a first conductivity type, the semiconductor substrate having a first surface and a second surface; forming a first semiconductor layer of a second conductivity type on the first surface of the semiconductor substrate, the first semiconductor layer having a first peak doping concentration; forming a first semiconductor region of the second conductivity type positioned between the semiconductor substrate and the first semiconductor layer, the first semiconductor region having a second peak doping concentration that is greater than the first peak doping concentration wherein at least a portion of the first semiconductor region forms a first zener diode with the semiconductor substrate; forming a second semiconductor region of the first conductivity type within a first portion of the first semiconductor layer, the second semiconductor region having a second peak doping concentration that is greater than the first peak doping concentration, wherein the second semiconductor region forms a control electrode of a first transistor; forming a first isolation structure surrounding a periphery of the first portion of the first semiconductor region; forming a third semiconductor region within the second semiconductor region with the third semiconductor region having the second conductivity type wherein the third semiconductor region forms a first current carrying electrode of the first transistor; and forming a second isolation structure surrounding a periphery of a second portion of the first semiconductor region that is external to the first portion of the first semiconductor region wherein the second portion of the first semiconductor region forms a first diode having a first current carrying electrode coupled to the first current carrying electrode of the first zener diode and having a second current carrying electrode coupled to an input of the ESD device.