US 11,967,650 B2
Snapback electrostatic discharge protection device with tunable parameters
Sagar Saxena, Manchester, NH (US); Washington Lamar, Mont Vernon, NH (US); Maxim Klebanov, Palm Coast, FL (US); Chung C. Kuo, Manchester, NH (US); Sebastian Courtney, Dracut, MA (US); and Sundar Chetlur, Frisco, TX (US)
Assigned to Allegro MicroSystems, LLC, Manchester, NH (US)
Filed by Allegro MicroSystems, LLC, Manchester, NH (US)
Filed on May 5, 2022, as Appl. No. 17/662,101.
Prior Publication US 2023/0361223 A1, Nov. 9, 2023
Int. Cl. H01L 29/87 (2006.01); H01L 29/06 (2006.01)
CPC H01L 29/87 (2013.01) [H01L 29/0684 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A diode comprising:
a substrate having a first type dopant;
a buried layer having a second type dopant and formed within the substrate;
an epitaxial layer having the second type dopant and formed above the buried layer;
a plurality of regions having the first type dopant within the epitaxial layer, wherein the plurality of regions comprises a first region, a second region, a third region, and a fourth region;
a base well having the first type dopant and located within the epitaxial layer and in contact with the third and fourth regions;
a first well having the second type dopant and formed in the epitaxial layer;
a second well having the first type dopant, and formed in the epitaxial layer, the second well extending into the first region;
a third well having the first type dopant located in the epitaxial layer and connected to the base well and connected to the second region and to the fourth region;
an anode;
a first heavily doped region having the second type dopant connected to the anode and the base well;
a second heavily doped region having the second type dopant connected to the anode and the base well; and
a cathode,
wherein in a reverse-bias mode, the diode is an electrostatic discharge (ESD) clamp and forms parasitic transistors comprising a first bipolar junction transistor (BJT), a second BJT and a third BJT.