Silicon Laser Annealing for Dopant Activation and Lifetime Killers
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Solution Overview
Problem
Existing methods for manufacturing semiconductor devices, such as IGBTs, require additional steps for generating lifetime killers, which increase manufacturing complexity and may not achieve a high enough activation rate without post-treatment to eliminate defects.
Innovation Solution
The method involves ion implantation of dopants into a silicon substrate followed by laser annealing to generate {311} defects and dislocation loops, which act as lifetime killers without the need for additional implantation steps, using a quasi-continuous wave laser to activate the dopants and control defect formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional implantation steps are used to generate lifetime killers, then the effectiveness of lifetime killers is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent combines the lifetime killer generation function with the existing dopant activation annealing process by performing laser annealing. This merging eliminates the need for separate lifetime killer generation steps while achieving both dopant activation and defect formation simultaneously, thereby improving manufacturing efficiency without sacrificing reliability.
Solution Approach 2:
The laser annealing process serves multiple functions: it activates implanted dopants, generates lifetime killers through point defect formation, and can control the depth and distribution of both dopants and defects. This multi-functionality reduces the total number of process steps while maintaining effective lifetime killer generation.
2Productivity
If conventional annealing is used to activate dopants, then the activation rate is improved, but additional steps are required to generate lifetime killers
Solution Approach 1:
The patent merges dopant activation and lifetime killer generation into a single laser annealing step. The laser annealing process simultaneously activates dopants and generates point defects that evolve into lifetime killers, eliminating the need for separate processing steps and reducing overall manufacturing time.
Solution Approach 2:
The patent utilizes specific laser parameters (wavelength, pulse duration, energy density) to control the annealing process. By optimizing these parameters, the process achieves high dopant activation rates while simultaneously generating the desired point defects that form lifetime killers, accomplishing both goals in one step.
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 allows for the generation of effective lifetime killers within the semiconductor device manufacturing process without increasing the number of steps, achieving a high activation rate and utilizing defects like {311} defects and dislocation loops as intended, even when they remain post-annealing.
Implementation Method 1
perform laser annealing on a silicon substrate in which point defects are generated due to ion implantation of a dopant to activate the dopant
Implementation Method 2
a pulsed laser beam having a wavelength of 600 nm to 1200 nm and a pulse width of 10 μs to 100 μs is used
Implementation Method 3
ion implantation of a dopant to activate the dopant
Data Source
AI summary
A method of manufacturing a semiconductor device includes: performing laser annealing on a silicon substrate in which point defects are generated due to ion implantation of a dopant to activate the dopant; and growing the point defects into {311} defects or dislocation loops and using the {311} defects or the dislocation loops as lifetime killers.