Patent ID: 11955514
Assignee: GLOBALFOUNDRIES U.S. INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 12:
13. A method of forming a device, comprising:
forming a first trench in a substrate having a lower surface;
forming a second trench in the substrate adjacent to and connected to the first trench, wherein the second trench has a greater depth than the first trench, relative to an upper surface of the substrate;
filling the first trench and the second trench with a dielectric material to a level substantially coplanar with an upper surface of the substrate before forming a gate structure, wherein the first trench and the second trench form a first portion and a second portion of a trench isolation structure, respectively, wherein a lower surface of the first portion is above a lower surface of the second portion;
forming the gate structure in the substrate adjacent to the trench isolation structure; and
forming a source region and a drain region in the substrate at opposite sides of the trench isolation structure, wherein the drain region is in contact with the second portion of the trench isolation structure.