Semiconductor device and method of manufacturing the same
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Solution Overview
Problem
Semiconductor devices, such as IGBTs, face challenges in suppressing voltage oscillations during switching due to the spread of the depletion layer, which reduces carrier concentration and shortens carrier lifetime, especially when proton irradiation forms crystal defects that persist even after annealing.
Innovation Solution
A semiconductor device structure with a hydrogen concentration of 5×10^17 atoms/cm^3 in the second buffer layer, formed by proton irradiation followed by hydrogen plasma treatment and annealing, effectively terminates crystal defects, increasing carrier lifetime and suppressing voltage oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If proton irradiation is performed to form crystal defects, then carrier lifetime is increased, but voltage oscillations occur due to depletion layer spread
Solution Approach 1:
The patent applies local quality by creating a buffer layer with specific hydrogen concentration (5×10^17 to 5×10^18 atoms/cm³) at a specific depth (0.5-2.0 μm from surface) while maintaining different properties in other regions. This localized hydrogen-rich zone terminates crystal defects precisely where needed without affecting the overall device structure, resolving the contradiction between extended carrier lifetime and voltage oscillation suppression.
Solution Approach 2:
The patent changes the hydrogen concentration parameter in the buffer layer to a specific range (5×10^17 to 5×10^18 atoms/cm³) through plasma treatment and ion implantation. This parameter optimization allows the buffer layer to effectively terminate crystal defects formed by proton irradiation, thereby suppressing voltage oscillations while maintaining the extended carrier lifetime benefit.
2Reliability
If annealing is performed to reduce crystal defects, then device reliability improves, but carrier lifetime remains shortened due to persistent defects
Solution Approach 1:
The patent introduces hydrogen as an intermediary substance that binds to crystal defects formed by proton irradiation. The buffer layer with controlled hydrogen concentration acts as a mediator that captures and neutralizes residual defects after annealing, preventing them from acting as carrier recombination centers. This allows the device to maintain both high reliability and extended carrier lifetime.
Solution Approach 2:
The patent creates a composite structure consisting of the semiconductor substrate and a buffer layer with specific hydrogen concentration. This composite approach combines the benefits of proton irradiation (extended carrier lifetime) with the defect-passivating effect of hydrogen-rich material, achieving both improved reliability and maintained carrier lifetime.
3Reliability
If hydrogen plasma treatment is applied to increase hydrogen concentration, then carrier traps are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies hydrogen plasma treatment as a preliminary step before final device fabrication to pre-load the buffer layer with hydrogen. This preliminary action ensures that when proton irradiation and annealing occur later, the hydrogen is already in place to terminate crystal defects, simplifying the overall manufacturing process by consolidating defect management into an early 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
The high hydrogen concentration in the second buffer layer significantly reduces carrier traps, increases carrier lifetime, and effectively suppresses voltage oscillations, enhancing the performance of semiconductor devices like IGBTs.
Implementation Method 1
the semiconductor layer having a hydrogen concentration of 5×10^17 atoms/cm^3 or more in a depth direction
Implementation Method 2
performing hydrogen plasma treatment on the first surface; annealing the semiconductor substrate
Implementation Method 3
A semiconductor device structure with a hydrogen concentration of 5×10^17 atoms/cm^3 in the second buffer layer, formed by proton irradiation followed by hydrogen plasma treatment and annealing, effectively terminates crystal defects
Implementation Method 4
performing hydrogen plasma treatment on the first surface; annealing the semiconductor substrate
Data Source
AI summary
Provided is a semiconductor device including: a first semiconductor layer of a first conductivity type, and the first semiconductor layer including first conductivity type impurities; a second semiconductor layer of the first conductivity type provided on the first semiconductor layer, and the second semiconductor layer including lower first conductivity type impurities than the first semiconductor layer; and a third semiconductor layer provided in the first semiconductor layer, and the third semiconductor layer including a hydrogen concentration of 5×1017 atoms/cm3 or more.