Stacked Channel MOSFET Gate Thickness for Scaling Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling down of metal oxide semiconductor field effect transistors (MOSFETs) in semiconductor devices leads to deteriorated operating characteristics and reduced reliability.
Innovation Solution
A semiconductor device design featuring a gate electrode with varying thickness parts surrounding channel structures of different heights, including a thicker lower part and thinner upper part, connected by channel structures with varying numbers of semiconductor patterns, to enhance electrical properties and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOSFET sizes are scaled down to increase integration, then device density increases, but operating characteristics deteriorate and reliability decreases
Solution Approach 1:
The patent transitions from planar 2D channel structures to three-dimensional vertically-stacked channel structures. Multiple channel structures are stacked vertically above the substrate, enabling increased device density without further lateral scaling. This vertical dimensionality change allows maintaining transistor performance while achieving higher integration density.
Solution Approach 2:
The gate electrode is divided into multiple discrete gate electrodes, each controlling a separate channel structure. This segmentation allows independent optimization of each transistor's electrical characteristics and enables selective gating control, improving overall device reliability while maintaining high density.
2Ease of operation
If gate electrode thickness is increased to improve transistor control, then switching capability improves, but power consumption increases
Solution Approach 1:
Different gate electrode portions have different thicknesses optimized for their specific functions. The gate electrode adjacent to the substrate has greater thickness for strong control, while upper gate portions have reduced thickness. This local quality variation maintains effective switching control while minimizing overall power consumption.
Solution Approach 2:
The gate electrode structure is asymmetric with varying thickness throughout its height. The thicker lower portion provides strong electrostatic control for switching, while the thinner upper portion reduces parasitic capacitance and power consumption. This asymmetric design optimizes both switching capability and energy efficiency.
Data Source
AI summary
A semiconductor device comprises an active pattern on a substrate, a pair of first source/drain patterns on the active pattern, a pair of second source/drain patterns on top surfaces of the first source/drain patterns, a gate electrode extending across the active pattern and having sidewalls that face the first and second source/drain patterns, a first channel structure extending across the gate electrode and connecting the first source/drain patterns, and a second channel structure extending across the gate electrode and connecting the second source/drain patterns. The gate electrode includes a first lower part between a bottom surface of the first channel structure and a top surface of the active pattern, and a first upper part between a top surface of the first channel structure and a bottom surface of the second channel structure. The first lower part has a thickness greater than that of the first upper part.