Plasma Doping Fin-FETs with Oxygen for Low Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma doping techniques struggle to form low-resistance impurity regions on the side surfaces of fin-semiconductor regions in fin-FETs due to insufficient impurity adsorption and activation, leading to difficulties in achieving desired transistor properties.
Innovation Solution
Incorporating a slight amount of oxygen into the plasma doping process using impurity-containing gases like AsH3, which forms a thin oxide layer to reduce impurity diffusion and enhance activation through oxidation-enhanced diffusion, thereby reducing the resistance in the impurity regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma doping is performed without oxygen-containing gas, then impurity adsorption is enhanced, but resistance in the impurity region cannot be sufficiently reduced
Solution Approach 1:
The patent changes the chemical composition parameter of the plasma environment by introducing oxygen-containing gas (O2, H2O, N2O, or CO2) at controlled concentrations (0.01-5% by mass) to modify the doping mechanism and achieve lower resistance through oxidation-enhanced diffusion
Solution Approach 2:
The patent introduces oxygen as an intermediary substance that facilitates impurity activation and reduces resistance through oxidation-enhanced diffusion, acting as a mediator between the impurity atoms and the semiconductor lattice
2Manufacturing precision
If oxygen-containing gas is added to plasma doping, then resistance in impurity region is reduced, but oxidation of fin-semiconductor region may occur
Solution Approach 1:
The patent precisely controls the oxygen concentration parameter (0.01-5% by mass) and process conditions to enable oxidation-enhanced diffusion while suppressing harmful oxidation of the fin-semiconductor region, transforming oxidation from a harmful effect to a useful mechanism
Solution Approach 2:
The patent creates different local conditions: oxidation-enhanced diffusion occurs locally at the impurity doping sites to reduce resistance, while the overall fin-semiconductor region is protected from harmful oxidation through controlled plasma parameters and timing
3Ease of operation
If ion implantation is performed in oblique direction, then side portions of fin-type silicon region are doped, but doping uniformity is poor and resistance is high
Solution Approach 1:
The patent replaces the mechanical ion implantation process with a plasma-based chemical doping process, where impurity atoms are transported and incorporated through plasma chemistry and diffusion mechanisms rather than mechanical ion bombardment, achieving uniform doping without oblique angle requirements
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 effectively reduces the resistance in the impurity regions of fin-semiconductor devices, enabling the formation of fin-type semiconductor devices with desired properties by improving impurity activation and minimizing issues like amorphization and corner chipping.
Implementation Method 1
Incorporating a slight amount of oxygen into the plasma doping process using impurity-containing gases like AsH3, which forms a thin oxide layer to reduce impurity diffusion and enhance activation through oxidation-enhanced diffusion
Implementation Method 2
plasma doping process using impurity-containing gases like AsH3
Implementation Method 3
enhance activation through oxidation-enhanced diffusion
Data Source
AI summary
After a fin-semiconductor region (13) is formed on a substrate (11), impurity-containing gas and oxygen-containing gas are used to perform plasma doping on the fin-semiconductor region (13). This forms impurity-doped region (17) in at least side portions of the fin-semiconductor region (13).