Multi-Gate Channel Trimming via Etch Rate Modulation
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Solution Overview
Problem
The integration of gate-all-around field effect transistor (GAA FET) devices faces challenges due to extruding end portions of channel layers, which introduce non-uniformity and high resistance, leading to degraded chip performance, as conventional etching methods to trim these portions can cause pun-through leakage.
Innovation Solution
An etch rate modulation is applied by implanting etch rate modifying species into the channel layers, combined with a selective etching process to shrink the extruding end portions, improving channel length uniformity and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to trim extruding end portions of channel layers, then channel length uniformity is improved, but pun-through leakage occurs due to source/drain trenches extending deeper into the substrate
Solution Approach 1:
The patent applies different etch rates to different regions of the channel layers by implanting etch rate modifying species (such as nitrogen or carbon ions) into specific zones. The extruding end portions receive higher doses of etch rate modifying species to increase their etch rate, while the main channel body maintains its original etch rate. This local differentiation allows selective trimming of extruding portions without affecting the overall channel structure or causing pun-through leakage.
Solution Approach 2:
The etch rate modifying species are implanted into the channel layers before the final etching process. This preliminary modification of the channel layer properties enables the subsequent etching process to selectively remove extruding end portions at a different rate than the main channel body, achieving uniform channel lengths without extending trenches deeper into the substrate.
2Ease of manufacture
If etching process is used to form source/drain trenches, then source/drain regions are formed, but extruding end portions of channel layers are created causing non-uniformity and high resistance
Solution Approach 1:
The patent introduces spatial variation in the etch rate of channel layers by implanting etch rate modifying species into specific regions. The extruding end portions are targeted with higher concentrations of etch rate modifying species, creating a local property difference that enables selective removal of these portions in subsequent etching steps, thereby achieving uniform channel lengths while maintaining ease of source/drain trench formation.
Solution Approach 2:
The patent changes the etch rate parameter of channel layers by implanting etch rate modifying species such as nitrogen or carbon ions. This parameter change is applied non-uniformly across the channel layer, with higher concentrations at extruding end portions, enabling differential etching that trims these portions without affecting the main channel body or requiring more complex manufacturing processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances channel length uniformity and reduces channel resistance, thereby improving the performance of GAA FET devices by selectively trimming the extruding end portions without extending the source/drain trenches deeper into the substrate.
Implementation Method 1
implanting etch rate modifying species into the channel layers
Data Source
AI summary
The present disclosure provides a semiconductor device and a method of manufacturing the semiconductor device. The semiconductor device includes channel members disposed over a substrate, a gate structure engaging the channel members, and an epitaxial feature adjacent the channel members. At least one of the channel members has an end portion in physical contact with an outer portion of the epitaxial feature. The end portion of the at least one of the channel members includes a first dopant of a first concentration. The outer portion of the epitaxial feature includes a second dopant of a second concentration. The first concentration is higher than the second concentration.