Asymmetrical Gate Electrode Tabs for Semiconductor HEIP Reduction
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Solution Overview
Problem
In highly integrated semiconductor devices, particularly PMOS transistors, hot electron induced punchthrough (HEIP) occurs due to electrons being trapped in device isolation regions and gate insulating layers, reducing channel length and causing leakage current, especially when the channel length is already minimized by small design rules.
Innovation Solution
The semiconductor device incorporates asymmetrical gate electrodes with protruding tabs and larger contact plugs on the source and drain regions, preventing electron trapping and enhancing on-current by maximizing contact plug size, thereby reducing the likelihood of HEIP and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the channel length is reduced to meet small design rules for high integration, then device integration is improved, but hot electron induced punchthrough (HEIP) occurs due to electron trapping in device isolation regions and gate insulating layers
Solution Approach 1:
The gate electrode structure employs asymmetrical design with gate tabs extending over the device isolation region on one side but not the other. This asymmetrical configuration creates an electrical field distribution that prevents electron trapping at the device isolation region interface, thereby eliminating HEIP while maintaining reduced channel length for high integration
Solution Approach 2:
The gate tabs extend the gate electrode structure into a third dimension by protruding over the device isolation region. This dimensional extension creates an additional electrical field region that suppresses electron trapping at the isolation region boundary, solving the HEIP problem without increasing the planar channel length
2Reliability
If asymmetrical gate tabs are added to prevent electron trapping, then HEIP is reduced, but device structure becomes more complex
Solution Approach 1:
The gate tabs are formed as an integrated extension of the main gate electrode structure using the same conductive material and formation process. This merging approach prevents electron trapping while avoiding the complexity of separate components, as the tabs are essentially an extended version of the existing gate structure
Data Source
AI summary
A semiconductor device includes an active region defined by a device isolation layer and including first and second sections or regions, a gate electrode extending in a first direction across the active region over a channel between the first region and the second region and including at least one first gate tab protruding in a second direction toward the first region, and first and second contact plugs. The first gate tab covers and extends along a boundary between the active region and the device isolation layer. The first contact plug is disposed over the first region, the second contact plug is disposed over the second region, and the second contact plug has an effective width, as measured in the first direction, greater than that of the first contact plug.