IGBT Gradual PN Junction via Metal Ion Doping
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Solution Overview
Problem
The abrupt PN junction in current IGBTs limits the improvement of performance metrics such as breakdown voltage and turn-off time due to the physical properties of boron ions used for doping.
Innovation Solution
Doping a target region in the IGBT with ions having a higher diffusion coefficient than boron ions, such as aluminum, gallium, or indium ions, to form a gradual PN junction, and optionally using boron ions on the contact surface to prevent metal contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If boron ions are used for doping the target region, then the doping process is simple and well-established, but the PN junction formed is abrupt which limits breakdown voltage and turn-off time performance
Solution Approach 1:
The patent changes the doping parameter from boron ions to metal ions (aluminum, gallium, indium, or thallium) which have larger ionic radii. This parameter change results in a gradual PN junction instead of an abrupt junction, thereby improving breakdown voltage and turn-off time performance without significantly complicating the doping process
Solution Approach 2:
The patent employs a composite doping approach by introducing metal ions with specific physical properties (larger ionic radius) into the semiconductor structure. This creates a composite doping profile that achieves both gradual junction formation and maintains process feasibility
2Reliability
If metal ions with larger ionic radius are used for doping, then a gradual PN junction is formed improving performance, but the doping process becomes more complex
Solution Approach 1:
The patent utilizes the parameter change of ionic radius by selecting metal ions (aluminum, gallium, indium, thallium) that are larger than boron ions. This physical parameter change enables gradual impurity distribution that improves anti-latch-up ability while the doping methods (ion implantation, diffusion, evaporation, or sputtering) remain within existing manufacturing capabilities
3Reliability
If a gradual PN junction is formed through ion doping, then breakdown voltage increases, but the doping time and temperature requirements may increase
Solution Approach 1:
The patent changes the doping ion type to metal ions with larger radii, which naturally produce gradual distribution profiles. This parameter change achieves higher breakdown voltage while the doping process can be optimized for time and temperature based on the specific metal ion used and the desired junction characteristics
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 results in increased breakdown voltage, shorter turn-off time, improved anti-latch-up ability, and enhanced IGBT performance with a wider and deeper PN junction formed at lower temperatures and in shorter times, offering cost advantages.
Implementation Method 1
the first ions are doped into the target region through any one of ion implantation, diffusion, evaporation, and sputtering
Implementation Method 2
the diffusion coefficient of the first ions is greater than the diffusion coefficient of boron ions
Implementation Method 3
the diffusion coefficient of the first ions is greater than the diffusion coefficient of boron ions... the impurity distribution morphology formed under the same conditions is more gradual
Implementation Method 4
the contact surface between the target region and other regions in the IGBT is doped with boron ions
Data Source
AI summary
An IGBT and a manufacturing method therefor, wherein a target region in the IGBT is doped with first ions; the target region comprises at least one of a P-type substrate (11), a P-type well region (13), and a P-type source region (14); and the diffusion coefficient of the first ions is greater than the diffusion coefficients of boron ions. A PN junction formed by means of the present invention is a gradual junction, thereby improving breakdown voltage, shortening turn-off time, and improving anti-latch capability.