Ultra-shallow Impurity Profile Control via Plasma Doping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of semiconductor devices requires a high-accuracy technique to form shallow impurity regions with depths of 50 nm or less, and achieving a stable, box-shaped impurity concentration profile is challenging due to the difficulty in controlling the impurity introduction process, especially in ultra-shallow regions.
Innovation Solution
An impurity introducing method involving the introduction of desired impurities into a semiconductor substrate followed by low-energy plasma radiation, which imparts vertical dynamic energy to the impurities, allowing for precise control of the impurity concentration profile, forming a box-shaped distribution without lateral spreading, and subsequent high-temperature flash-lamp annealing to maintain the profile and reduce sheet resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion implantation is used to form shallow junction, then impurity can be introduced into substrate, but the depth of ion introduced region is limited to approximately 10 nm from surface and acceleration energy cannot be set to low energy of several keV
Solution Approach 1:
The invention changes the fundamental parameters of the doping process by using plasma doping instead of ion implantation. This allows the acceleration energy to be reduced to several keV while still achieving effective impurity introduction, thereby enabling precise control of junction depth at ultra-shallow levels of 10 nm or less.
Solution Approach 2:
The invention replaces the mechanical ion implantation system with a plasma-based doping system. This substitution eliminates the need for high acceleration energy and mechanical ion beam delivery, allowing for gentler impurity introduction at ultra-shallow depths through plasma excitation and surface diffusion mechanisms.
2Manufacturing precision
If plasma doping is used to form shallow junction, then shallower junction with depth of 7 nm can be formed, but control technique with high accuracy for impurity introduction is still demanded for depths of 50 nm or less and 10 nm
Solution Approach 1:
The invention applies preliminary plasma treatment to the substrate surface before impurity introduction. This preliminary plasma exposure modifies the surface conditions and prepares it for controlled impurity uptake, enabling stable and repeatable ultra-shallow doping profiles with high accuracy at depths of 50 nm or less and 10 nm.
Solution Approach 2:
The invention implements feedback control mechanisms to monitor and adjust the plasma doping process parameters in real-time. This ensures stable control of impurity introduction depth and concentration, achieving reliable ultra-shallow junction formation with precise depth control at 10 nm or less.
3Manufacturing precision
If impurity is introduced into ultra-shallow region, then shallow junction is formed, but impurity concentration profile exhibits high concentration in vicinity of surface and sharp change as depth is increased making box-shaped control extremely difficult
Solution Approach 1:
The invention uses periodic plasma pulsing during the doping process to control impurity introduction. By applying plasma in periodic pulses rather than continuous exposure, the method achieves gradual and controlled impurity distribution that approximates the desired box-shaped profile, reducing the sharp concentration gradients that normally occur in ultra-shallow regions.
Solution Approach 2:
The invention dynamically adjusts plasma power, gas flow rates, and substrate temperature during the doping process to control impurity diffusion. This dynamic control enables the formation of a box-shaped concentration profile by modulating the plasma conditions to match the target depth and concentration distribution 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
This method enables the formation of stable, ultra-shallow impurity regions with high concentration at the surface, achieving a box-shaped impurity profile that reduces sheet resistance and enhances operational speed, suitable for high-speed semiconductor devices.
Implementation Method 1
radiating plasma to a surface of the solid base body after the above-mentioned impurity introducing step
Implementation Method 2
a reaction gas containing impurity to be introduced is excited in plasma and the plasma is radiated to a surface of the substrate
Implementation Method 3
subsequent high-temperature flash-lamp annealing to maintain the profile and reduce sheet resistance
Data Source
AI summary
An impurity region having a box-shaped impurity profile is formed.An impurity introducing method includes a step of introducing a desired impurity into a surface of a solid base body, and a step of radiating plasma to a surface of the solid base body after the impurity introducing step thus forming an impurity profile having an approximately box-shape.