US 12,363,926 B2
Vertical deep trench and deep trench island based deep n-type well diode and diode triggered protection device
Umamaheswari Aghoram, Richardson, TX (US); Akram Ali Salman, Plano, TX (US); Binghua Hu, Plano, TX (US); and Alexei Sadovnikov, Sunnyvale, CA (US)
Assigned to TEXAS INSTRUMENTS INCORPORATED, Dallas, TX (US)
Filed by Texas Instruments Incorporated, Dallas, TX (US)
Filed on Nov. 20, 2023, as Appl. No. 18/514,413.
Application 18/514,413 is a division of application No. 17/459,991, filed on Aug. 27, 2021, granted, now 11,869,986.
Prior Publication US 2024/0088305 A1, Mar. 14, 2024
Int. Cl. H10D 8/25 (2025.01); H10D 8/01 (2025.01); H10D 89/60 (2025.01)
CPC H10D 8/25 (2025.01) [H10D 8/022 (2025.01); H10D 89/611 (2025.01); H10D 89/711 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A method of forming a semiconductor device, comprising:
forming a semiconductor layer on a substrate;
forming a first trench and a second trench in the semiconductor layer, wherein:
the first trench has a first footprint with a first area; and
the second trench has a second footprint with a second area same as the first area;
forming a doped trench liner in the first trench and the second trench, the doped trench liner being a first conductivity type;
heating the substrate such that a doped sheath forms in the substrate as a result of heating the substrate, the doped sheath contacting and laterally surrounding the first trench and the second trench;
forming a doped region of the first conductivity type contacting the doped sheath to form a cathode of a Zener diode; and
forming a doped region of a second conductivity type contacting the doped sheath between the first trench and the second trench to form an anode of the Zener diode.