Semiconductor Gate Edge Protrusion for Punchthrough Relief
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Solution Overview
Problem
As semiconductor devices shrink to 100 nm or less, the hot electron induced punchthrough phenomenon occurs, leading to reduced electrical characteristics, increased power consumption, and decreased breakdown voltage, particularly in PMOS transistors, due to undesired channel inversion and leakage currents, which existing solutions attempt to address by using gate taps that increase die size and complicate integration.
Innovation Solution
A semiconductor device and fabrication method that form a protrusion on the substrate's edge where the active region contacts the isolation region under the gate pattern, increasing channel length without using a gate tap, by forming a three-dimensional structure with a higher surface than the substrate, and integrating a gate insulation and conductive layers to prevent channel inversion and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate tap is installed to increase channel length and relieve HEIP phenomenon, then transistor breakdown voltage is improved, but die size increases and integration density decreases
Solution Approach 1:
The patent introduces a three-dimensional protrusion structure at the gate edge that extends vertically from the substrate surface. This vertical dimension allows the channel length to be effectively increased without occupying additional horizontal planar space, thereby relieving the HEIP phenomenon and improving breakdown voltage while maintaining compact die size and high integration density.
Solution Approach 2:
The protrusion structure is localized specifically at the gate edge region where the active region contacts the isolation region, rather than uniformly extending the channel throughout. This localized modification targets the specific area where HEIP occurs, providing the necessary channel length extension only where needed, thus avoiding unnecessary die size increase while improving breakdown voltage.
2Productivity
If channel length is reduced for high integration, then productivity and integration density are improved, but HEIP phenomenon worsens due to insufficient channel length
Solution Approach 1:
By utilizing the vertical dimension through the protrusion structure, the patent achieves effective channel length extension without increasing horizontal footprint. This allows short channel layouts to maintain adequate effective channel length for HEIP resistance while achieving high integration density and productivity through compact planar dimensions.
3Object-generated harmful factors
If gate edge channel length is increased to prevent channel inversion, then leakage current is reduced, but device complexity increases due to additional gate tap structure
Solution Approach 1:
The protrusion structure is integrated as part of the existing gate electrode and substrate structure, forming a unified continuous gate system. This merging approach prevents channel inversion and reduces leakage current without introducing separate or additional gate components, thereby avoiding increased device complexity while achieving the desired electrical performance.
Data Source
AI summary
A semiconductor device includes a substrate having an active region and an isolation region, a gate pattern crossing both the active region and the isolation region of the substrate, and a protrusion having a surface higher than that of the substrate over at least an edge of the active region contacting a portion of the isolation region under the gate pattern.