US 12,426,362 B2
Latch-up free high voltage device
Lijie Zhao, San Jose, CA (US); Kenneth Chung-Yin Kwok, Irvine, CA (US); Suming Lai, San Diego, CA (US); and Zhao Fang, Plano, TX (US)
Assigned to Halo Microelectronics International, Campbell, CA (US)
Filed by Halo Microelectronics International, Campbell, CA (US)
Filed on Aug. 4, 2021, as Appl. No. 17/393,875.
Prior Publication US 2023/0044360 A1, Feb. 9, 2023
Int. Cl. H10D 84/90 (2025.01); H03K 17/0814 (2006.01); H10D 8/01 (2025.01); H10D 8/60 (2025.01); H10D 84/01 (2025.01); H10D 84/03 (2025.01); H10D 84/40 (2025.01); H10D 84/85 (2025.01)
CPC H10D 84/991 (2025.01) [H03K 17/0814 (2013.01); H10D 8/051 (2025.01); H10D 8/60 (2025.01); H10D 84/0109 (2025.01); H10D 84/038 (2025.01); H10D 84/403 (2025.01); H10D 84/854 (2025.01)] 17 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a first drain/source region, a second drain/source region and a third drain/source region formed inside a well region having a first conductivity type, wherein the well region is surrounded by an isolation ring having a second conductivity type, wherein the isolation ring is floating, and the second drain/source region is formed in a body region and between the first drain/source region and the third drain/source region, and wherein the second drain/source region and the body region have two different conductivity types;
a buried layer having the second conductivity type formed between the well region and a substrate having the first conductivity type, wherein the buried layer is part of the isolation ring, and the substrate is in direct contact with the isolation ring and located below and outside of the isolation ring, while the well region is within the isolation ring;
a third diode formed between the substrate and the buried layer, wherein an anode of the third diode is connected to the substrate and a cathode of the third diode is connected to the buried layer; and
a first diode, wherein the first diode is a Schottky diode, and wherein an anode of the Schottky diode is a metal contact connected to a metal contact of the substrate through a suitable semiconductor interconnect device and a cathode of the Schottky diode is a region having the second conductivity type, and wherein the region is connected to the buried layer, and wherein:
the cathode of the Schottky diode is an N-type region, and wherein:
a first P-type well is formed in the N-type region; and
a second P-type well is formed in the N-type region, and wherein:
a portion of the N-type region between the first P-type well and the second P-type well is in direct contact with a the metal contact of the Schottky diode;
the metal contact of the Schottky diode comprises an upper portion and a lower portion, and three sides of the upper portion is surrounded by the lower portion;
a rightmost edge of the first P-type well is vertically aligned with a first sidewall of the upper portion; and
a leftmost edge of the second P-type well is vertically aligned with a second sidewall of the upper portion.