FET Body Resistance Reduction via Perpendicular Discharge Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices with field effect transistors (FETs) experience increased body resistance with wider gate widths due to parallel discharge paths, limiting their performance in logic and analog devices.
Innovation Solution
The semiconductor device design features a discharge path between the active gate and the body that is substantially perpendicular to the gate width, along with an inactive gate structure and shallow trench isolations, which reduces body resistance by shortening the discharge path and allowing for a self-balanced body potential shared among multiple transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the gate width is increased to improve current carrying capacity, then the device can handle higher currents, but the body resistance increases due to the parallel discharge path configuration
Solution Approach 1:
The discharge path is reconfigured from a parallel orientation (along the gate width direction) to a perpendicular orientation (transverse to the gate width). This dimensional change in the discharge path configuration allows the body resistance to remain low even when the gate width is increased for higher current capacity, as the charge can exit through a shorter, more direct path beneath the gate.
2Ease of manufacture
If the discharge path is oriented parallel to the gate width to simplify structure, then the fabrication is easier, but the body resistance increases with wider gates
Solution Approach 1:
The discharge path transitions from a parallel configuration to a perpendicular configuration relative to the gate width. This reorientation maintains fabrication simplicity while dramatically reducing body resistance by creating a shorter, more efficient charge discharge route that does not scale with gate width.
3Reliability
If multiple transistors share a common body to reduce resistance, then the body resistance decreases, but the body potential becomes unbalanced affecting transistor performance
Solution Approach 1:
The common body is segmented into individual body regions for each transistor, with each transistor having its own dedicated discharge path to its respective body region. This segmentation maintains low body resistance through direct discharge paths while preserving body potential balance by isolating each transistor's electrical characteristics, preventing interference between adjacent devices.
Solution Approach 2:
Each transistor is provided with locally optimized body connections and discharge paths tailored to its specific requirements. This local quality approach allows each transistor to maintain its own body potential while collectively achieving low resistance through parallel independent discharge paths, resolving the conflict between common body resistance reduction and potential balance.
Data Source
AI summary
Embodiments of the invention relate generally to semiconductor devices and, more particularly, to semiconductor devices having field effect transistors (FETs) with a low body resistance and, in some embodiments, a self-balanced body potential where multiple transistors share same body potential. In one embodiment, the invention includes a field effect transistor (FET) comprising a source within a substrate, a drain within the substrate, and an active gate atop the substrate and between the source and the drain, an inactive gate structure atop the substrate and adjacent the source or the drain, a body adjacent the inactive gate, and a discharge path within the substrate for releasing a charge from the FET, the discharge path lying between the active gate of the FET and the body, wherein the discharge path is substantially perpendicular to a width of the active gate.