Substrate isolation in integrated circuits

Details Substrate isolation in integrated circuits Substrate isolation in integrated circuits

2008-04-15

2008-04-15

Smoot, Stephen W. (Department: 2813)

Semiconductor device manufacturing: process

Formation of electrically isolated lateral semiconductive...

Grooved and refilled with deposited dielectric material

C438S525000, C257SE21551

Reexamination Certificate

active

07358149

ABSTRACT:
Substrate isolation trench (224) are formed in a semiconductor substrate (120). Dopant (e.g. boron) is implanted into the trench sidewalls by ion implantation to suppress the current leakage along the sidewalls. During the ion implantation, the transistor gate dielectric (520) faces the ion stream, but damage to the gate dielectric is annealed in subsequent thermal steps. In some embodiments, the dopant implantation is an angled implant. The implant is performed from the opposite sides of the wafer, and thus from the opposite sides of each active area. Each active area includes a region implanted from one side and a region implanted from the opposite side. The two regions overlap to facilitate threshold voltage adjustment.

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