Multi-threshold voltage field effect transistor and manufacturing method thereof

Abstract

The present disclosure provides an FET structure including a transistor of a first conductive type. The transistor includes a substrate having a region of a second conductive type, a channel between source and drain, and a gate over the channel. The channel includes dopants of the first conductive type. The gate includes a work function setting layer of the second conductive type. The present disclosure also provides a method for manufacturing an FET with multi-threshold voltages scheme. The method includes exposing channels of a first transistor of a first conductive type and a first transistor of a second conductive type from a first mask, doping the channels with dopants of the first conductive type, exposing channels of a second transistor of the first conductive type and a second conductive type from a second mask, and doping the channels with dopants of the second conductive type. The invention also provides a multi-threshold voltage field effect transistor and a manufacturing method thereof.

Description

technical field [0001] The present invention involves multiple threshold voltages (V t ) transistor field effect transistor (FET) structure and method of fabricating the FET structure. Background technique [0002] Multiple threshold voltage IC devices are commonly used in the semiconductor integrated circuit (IC) industry to optimize delay or power. A multi-threshold voltage IC device may include multiple different devices, each with a different threshold voltage (ie, operating voltage). For example, a multi-threshold voltage IC device may include a low threshold voltage device and a high threshold voltage device. One approach to realizing devices with different threshold voltages involves channel and halo implant optimization. This implements re-implantation to achieve larger threshold voltage devices and separates the masks for each desired threshold voltage. Note that heavier implantation processes can cause mobility degradation and junction leakage current, and usin...

AI Technical Summary

Problems solved by technology

Increasing channel length to accommodate larger threshold voltage devices thus consumes valuable IC device space, limiting the number of devices that can be fabricated on a single chip

Also, a larger channel length reduces the ON current and increases capacitance, thus reducing the speed of device operation

[0004] Thus, while existing methods for fabricating multi-threshold voltage devices are often adequate for their intended purpose, they cannot be made in all respects

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