Non-uniform Channel Junction-less Transistor Parasitic Resistance
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Solution Overview
Problem
Conventional FinFET devices suffer from high parasitic resistance due to uniform channel profiles, which adversely affects the magnitude of drain current.
Innovation Solution
A non-uniform channel profile is achieved by performing multiple implantation processes to form source/drain regions in the fin structure, resulting in a lower doping concentration under the gate and higher concentrations on either side, reducing parasitic resistance and enhancing drain current performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform channel profile is used in FinFET devices, then fabrication is simpler, but parasitic resistance increases and drain current performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping profile where the channel region under the gate has a different (lower) doping concentration compared to the source and drain regions. This local variation in doping concentration optimizes carrier transport in the channel while maintaining good ohmic contacts at source and drain, thereby reducing parasitic resistance and improving drain current performance without complicating the overall fabrication process
2Reliability
If multiple implantation processes are performed to create non-uniform doping profile, then parasitic resistance decreases and drain current improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the doping process into multiple sequential implantation steps, each targeting specific regions of the fin structure with different doping concentrations. The first implantation process dopes the source and drain regions, while the second process dopes the channel region under the gate. This segmented approach enables precise control over the doping profile to reduce parasitic resistance while keeping each individual implantation step relatively simple
3Reliability
If doping concentration under the gate is reduced, then parasitic resistance decreases and drain current increases, but control over channel becomes more difficult
Solution Approach 1:
The patent applies parameter changes by carefully controlling the doping concentration parameter in the channel region under the gate. By reducing the doping concentration in this specific region compared to conventional uniform doping, the patent enhances carrier mobility and reduces parasitic resistance, leading to higher drain current. The gate control effectiveness is maintained through precise control of the doping parameters and the three-dimensional FinFET structure that provides strong electrostatic control
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
The non-uniform doping profile significantly reduces parasitic resistance, leading to improved drain current performance while maintaining comparable leakage current and channel dose, with potential increases in drain current by at least 20% compared to conventional devices.
Implementation Method 1
performing multiple implantation processes to form source/drain regions in the fin structure
Data Source
AI summary
The present disclosure discloses a method of forming a semiconductor layer on a substrate. The method includes patterning the semiconductor layer into a fin structure. The method includes forming a gate dielectric layer and a gate electrode layer over the fin structure. The method includes patterning the gate dielectric layer and the gate electrode layer to form a gate structure in a manner so that the gate structure wraps around a portion of the fin structure. The method includes performing a plurality of implantation processes to form source/drain regions in the fin structure. The plurality of implantation processes are carried out in a manner so that a doping profile across the fin structure is non-uniform, and a first region of the portion of the fin structure that is wrapped around by the gate structure has a lower doping concentration level than other regions of the fin structure.