FinFET Epi-Extension Junction Control via Hydrogen Annealing
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Solution Overview
Problem
Dopant diffusion in FinFET junction engineering faces challenges such as damage to fins and undesirable resistance increases due to conventional implant methods, which struggle to provide effective doping between fins and gates while maintaining uniformity and minimizing thermal budget.
Innovation Solution
An annealing process is applied to create a gap between the fin and the spacer, allowing for the growth of an epitaxial semiconductor layer, which facilitates efficient doping and reduces junction gradients, thereby improving gate short channel control and minimizing fin damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional implant methods are used for doping, then doping can be achieved, but fin damage occurs and resistance increases
Solution Approach 1:
The patent replaces the mechanical implantation process with a chemical diffusion process. Instead of physically implanting dopants through high-energy ion bombardment that damages fins, the invention uses thermal diffusion where dopants naturally diffuse into the fin structure through heat treatment, eliminating mechanical damage while achieving uniform doping profiles
Solution Approach 2:
The patent changes the doping parameters by using low-temperature thermal diffusion instead of high-energy implantation. The doping process is controlled by temperature and time parameters, allowing precise control of dopant concentration and distribution without causing fin damage or resistance increase
2Manufacturing precision
If implants are used to achieve doping between fins and gate, then doping can be achieved, but fin damage and resistance increase occur
Solution Approach 1:
The patent substitutes the mechanical implantation method with thermal diffusion, allowing dopants to be delivered to specific locations (between fins and gate) through controlled thermal processes without the damaging effects of ion implantation, thus maintaining both doping location control and low fin resistance
Solution Approach 2:
The patent performs preliminary formation of the fin structure and gate before applying the thermal diffusion process. This preliminary preparation ensures that the subsequent doping occurs only in the desired regions between fins and gate, achieving precise location control without requiring high-energy implants that would damage the fins
3Manufacturing precision
If high thermal budget is used for doping, then doping can be achieved, but junction gradients increase and performance deteriorates
Solution Approach 1:
The patent optimizes the thermal diffusion parameters by using lower temperatures and controlled time durations. This parameter optimization allows achieving the required doping concentration while maintaining sharp junction gradients, preventing the diffusion spreading that occurs with high thermal budget 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
The method achieves a sharp extension junction with reduced thermal budget, minimizing series resistance and leakage current while maintaining dopant activation, resulting in improved transistor performance.
Implementation Method 1
applying an annealing process to the structure to create a gap between the at least one fin and the spacer
Implementation Method 2
growing an epitaxial semiconductor layer in the gap between the spacer and the at least one fin
Data Source
AI summary
Embodiments are directed to forming a structure comprising at least one fin, a gate, and a spacer, applying an annealing process to the structure to create a gap between the at least one fin and the spacer, and growing an epitaxial semiconductor layer in the gap between the spacer and the at least one fin.