Semiconductor device combining a MOSFET structure and a vertical-channel trench-substrate field effect device

Abstract

A semiconductor device that provides for substrate current exiting a MOSFET structure, and hence the performance thereof, to be independently and controllably tuned. The semiconductor device includes a semiconductor substrate of a first conductivity type, a conventional MOSFET structure disposed thereon, and at least one vertical-channel trench-substrate field effect device disposed in the semiconductor substrate. The vertical-channel trench-substrate field effect device includes a vertical-channel region beneath the MOSFET structure. During operation, substrate current exiting the MOSFET structure can be independently and controllably tuned by applying a potential bias to the vertical-channel trench-substrate field effect device that “pinches-off” the vertical-channel region. The vertical-channel trench-substrate field effect device includes an expanded trench that extends from an upper surface of the semiconductor substrate to beneath the MOSFET structure and a dielectric shallow trench spacer (e.g., silicon dioxide or silicon nitride dielectric shallow trench spacer) that is disposed along an upper portion of the sidewall of the expanded trench. The vertical-channel trench-substrate field effect device also includes a SiO2 trench liner layer disposed on those portions of the sidewall of the expanded trench that are not covered by the dielectric shallow trench spacer, and an electrically conductive trench fill layer (e.g., in-situ doped polysilicon) in the expanded trench. The vertical-channel region can be “pinched-off,” and the substrate current exiting the MOSFET structure independently and controllably tuned, by applying a potential bias to the electrically conductive trench fill layer. Also, a process for manufacturing the semiconductor device that is compatible with conventional IC manufacturing techniques.

Dependencies are inferred from the claim text.