Plasma Implanter for Simultaneous MOS Doping
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Solution Overview
Problem
The existing methods for manufacturing MOS transistors with gate lengths smaller than 100 nm require multiple implantation steps, leading to long processing times and high costs due to the use of separate implanters for different dopant types.
Innovation Solution
A method that utilizes a plasma implanter to simultaneously implant dopants of different types, with heavier dopants for surface regions and lighter dopants for deeper regions, by adjusting the biasing voltage and partial pressures in the plasma to achieve the desired doping profiles in a single step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple separate implantation steps are used for different dopant types, then precise control of doping profiles is achieved, but processing time increases and manufacturing costs increase
Solution Approach 1:
The patent combines multiple implantation steps for different dopant types (e.g., B+, BF+, BF2+, BF3+) into a single simultaneous implantation process. The plasma source generates multiple cation species that are implanted together, eliminating the need for separate implanters and sequential processing steps while maintaining precise control over the doping profile through adjusted implantation parameters.
Solution Approach 2:
The implantation device is designed to perform multiple functions by simultaneously implanting different dopant species in one step. The system can handle various cation types (B+, BF+, BF2+, BF3+) with different masses and implantation characteristics, making a single device replace multiple specialized implanters and reducing overall processing time.
2Manufacturing precision
If multiple separate implantation devices are used for different dopant types, then precise doping control is achieved, but device complexity and manufacturing costs increase
Solution Approach 1:
The patent merges the functionality of multiple separate implantation devices into a single plasma-based implantation system. This single device can generate and implant multiple cation species (B+, BF+, BF2+, BF3+) simultaneously, reducing the total number of devices required while maintaining the precision needed for different doping profiles.
Solution Approach 2:
The implantation device achieves multi-functionality by being capable of implanting various dopant types in one operation. The system handles different cation masses and implantation requirements through adjustable parameters, making one universal device replace multiple specialized devices and simplifying the overall manufacturing system.
3Manufacturing precision
If heavier dopants are used for surface regions and lighter dopants for deeper regions, then precise depth control is achieved, but the complexity of plasma parameter control increases
Solution Approach 1:
The patent utilizes parameter changes in the plasma environment to achieve precise depth control. By adjusting plasma power, gas flow rates, and bias voltage, the system controls the relative concentrations and implantation energies of different cation species (heavier vs. lighter dopants). This allows heavier dopants to concentrate in surface regions while lighter dopants penetrate deeper, achieving the desired doping profile through controlled parameter variations.
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 reduces the number of implantation steps, decreases processing time, and lowers costs by eliminating the need for separate implantation devices, while maintaining control over the channel region and minimizing short channel effects.
Implementation Method 1
a plasma implanter to simultaneously implant dopants of different types
Implementation Method 2
placed in the vicinity of a plasma comprising in the form of cations dopants of the first conductivity type and dopants of a second conductivity type
Implementation Method 3
negatively biasing the substrate placed in the vicinity of a plasma comprising in the form of cations dopants
Data Source
AI summary
A method for forming, in a single-crystal semiconductor substrate of a first conductivity type, doped surface regions of the second conductivity type and deeper doped regions of the first conductivity type underlying the surface regions, including the step of negatively biasing the substrate placed in the vicinity of a plasma including, in the form of cations dopants of the first conductivity type and dopants of a second conductivity type, the dopants of the second conductivity type having an atomic mass which is greater than that of the dopants of the first conductivity type.