Offset Source/Drain Layout in Nanostructure Transistors
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Solution Overview
Problem
As semiconductor devices miniaturize, nanostructure transistors face challenges such as increased short channel effects, electron tunneling, and reduced yield due to merging source/drain regions, leading to electrical shorting and device failures.
Innovation Solution
The source/drain regions in nanostructure transistors are staggered to increase the distance between them, reducing the likelihood of merging and enhancing yield and performance of nanostructure transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If source/drain regions are placed closer together to enable miniaturization, then device density increases, but source/drain regions merge leading to electrical shorting and reduced yield
Solution Approach 1:
The patent applies asymmetry by offsetting the source/drain regions in the lateral direction, creating an asymmetric configuration where the source and drain are not symmetrically positioned relative to the channel. This offset arrangement increases the effective distance between source/drain regions, preventing merging while enabling continued miniaturization and maintaining high device density.
2Length of moving object
If gate length is reduced for smaller technology nodes, then device size decreases, but electron tunneling increases leading to higher off current
Solution Approach 1:
The patent employs gate-all-around (GAA) nanostructure transistors that wrap the gate electrode around the channel in three dimensions, providing enhanced electrostatic control. This dimensional approach allows for shorter gate lengths while suppressing electron tunneling through improved electric field confinement, thereby reducing off-current despite miniaturization.
3Ease of manufacture
If conventional planar transistors are used, then manufacturing is simpler, but short channel effects significantly degrade performance at small nodes
Solution Approach 1:
The patent utilizes nanosheet channel structures that can be grown epitaxially with controlled thickness and composition gradients. The nanosheet architecture provides dynamic electrostatic control where the gate can effectively modulate the channel potential throughout the vertical dimension, suppressing short channel effects while maintaining manufacturability through established epitaxial growth techniques.
Data Source
AI summary
Nanostructure transistors are formed in a manner that may reduce the likelihood of source/drain region merging in the nanostructure transistors. In a top-down view of a nanostructure transistor described herein, source/drain regions on opposing sides of a nanostructure channel of the nanostructure transistor are staggered such that the distance between the source/drain regions is increased. This reduces the likelihood of the source/drain regions merging, which reduces the likelihood of failures and/or other defects forming in the nanostructure transistor. Accordingly, staggering the source/drain regions, as described herein, may facilitate the miniaturization of semiconductor devices that include nanostructure transistors while maintaining and/or increasing the semiconductor device yield of the semiconductor devices.