IGBT Low-Lifetime Region Ion Implantation
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Solution Overview
Problem
Existing IGBTs face challenges with high ion implantation doses leading to increased manufacturing costs, the need for specialized equipment, and reduced throughput due to multiple laser annealing processes, which affect the trade-off between on-state voltage and energy loss.
Innovation Solution
A semiconductor device with a low-lifetime region at the interface between the n− drift region and the p+ collector region, partially activated with a lower impurity concentration, formed using two ion implantations with different acceleration energies, allowing for simultaneous formation of the p+ collector region and low-lifetime region, reducing the need for specialized equipment and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lifetime control region is formed using ion implantation and annealing, then the trade-off between on-state voltage and energy loss is improved, but the manufacturing cost increases and throughput decreases
Solution Approach 1:
The invention performs ion implantation to form both the collector region and lifetime control region in advance, before the drift region is formed. This preliminary action allows the lifetime control region to be established early in the manufacturing process, eliminating the need for subsequent laser annealing steps and improving throughput while maintaining the desired electrical characteristics.
Solution Approach 2:
The invention combines the formation of the collector region and lifetime control region into a single ion implantation step. By using appropriate ion species and implantation conditions, both regions are created simultaneously, reducing the number of manufacturing steps and increasing productivity without compromising the trade-off between on-state voltage and energy loss.
2Reliability
If multiple laser annealing processes are used to form the lifetime control region, then the carrier lifetime is controlled, but the manufacturing cost increases and specialized equipment is required
Solution Approach 1:
The invention replaces the laser annealing process with a conventional ion implantation process. Instead of using laser energy to activate the lifetime control region, the invention uses ion implantation to directly create the region with the desired electrical characteristics. This substitution eliminates the need for specialized laser equipment and reduces manufacturing costs while maintaining effective carrier lifetime control.
Solution Approach 2:
The invention changes the approach from thermal activation (laser annealing) to direct ion implantation. By adjusting ion implantation parameters such as ion species, acceleration energy, and dose, the lifetime control region is formed with the appropriate electrical properties without requiring subsequent thermal processing steps.
3Loss of energy
If a low-lifetime region is provided at the interface between drift region and collector region, then on-state voltage and energy loss are reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The low-lifetime region is formed in advance through ion implantation before the drift region is created. This preliminary formation of the lifetime control region at the collector-drift interface simplifies the overall manufacturing process by establishing the critical low-lifetime zone early, which then guides subsequent processing steps rather than requiring additional complex operations.
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 on-state voltage and energy loss, lowers manufacturing costs, and enables efficient fabrication of IGBTs on a general manufacturing line by improving the trade-off relationship between on-state voltage and energy loss.
Implementation Method 1
a process of implanting a second conductivity type impurity with a second acceleration energy into the first semiconductor region into which the second conductivity type impurity has been implanted
Implementation Method 2
the surface of the first semiconductor region into which the second conductivity type impurity has been implanted is irradiated with a laser
Data Source
AI summary
A semiconductor device manufacturing method for a semiconductor device having a p-n junction formed of a first conductivity type first semiconductor region and a second conductivity type second semiconductor region, and comprising a low-lifetime region that has a carrier lifetime shorter than that in other regions at the interface of the p-n junction. The method includes an implantation process of, after implanting a second conductivity type impurity into the surface of the first semiconductor region with a first acceleration energy, implanting a second conductivity type impurity, with a second acceleration energy differing from the first acceleration energy, into the surface of the first semiconductor region into which the second conductivity type impurity has been implanted.