Substrate band gap engineered multi-gate pMOS devices

Abstract

A multi-gate transistor and a method of forming a multi-gate transistor, the multi-gate transistor including a fin having an upper portion and a lower portion. The upper portion having a first band gap and the lower portion having a second band gap with the first band gap and the second band gap designed to inhibit current flow from the upper portion to the lower portion. The multi-gate transistor further including a gate structure having sidewalls electrically coupled with said upper portion and said lower portion and a substrate positioned below the fin.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to the field of semiconductor devices and more specifically to controlling short-channel effects in multi-gate devices. [0003] 2. Discussion of Related Art [0004] During the past two decades, the physical dimensions of MOSFETs have been aggressively scaled for low-power, high-performance applications. The need for faster switching transistors requires shorter channel lengths. The continued decreasing size and need for low-power transistors makes overcoming the short channel effects of transistors necessary. However, as the dimensions of the transistors decrease the ability to control the leakage current becomes more difficult. To limit the amount of leakage current in a transistor current solutions involve strictly controlling the placement of the source and drain dopants within the active region of the transistor. Other techniques to combat the leakage current include implants in and a...

AI Technical Summary

Benefits of technology

[0006] A multi-gate transistor and a method of forming a multi-gate transistor, the multi-gate transistor including a fin having an upper portion and a lower portion. The upper portion having a first band gap and the lower portion having a second band gap with the first band gap and

Problems solved by technology

However, as the dimensions of the transistors decrease the ability to control the leakage current becomes more difficult.

However, the use of such implants results in degraded performance of the transistor such as increasing the threshold voltage.

Despite the better control over the channel, the multi-gate devices are less efficient at controlling the electric fields from the source and drain regions.

The electric fields from the source and drain regions result in short-channel effects such as an increased leakage current at a given gate voltage in the subthreshold region of device operation.

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