Schottky Electrode Structure for Lower Semiconductor Switching Loss
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Solution Overview
Problem
Semiconductor devices such as diodes and RC-IGBTs face challenges in minimizing switching loss due to carrier accumulation in the n-type cathode region during the on-state, which affects their switching speed and efficiency.
Innovation Solution
The semiconductor device design includes a second electrode with a first part and a second part, where the first part is located in the p-type anode region and has a greater length than the second part, forming a Schottky junction that reduces carrier injection and accumulation in the n-type cathode region, and the p-type impurity concentration is optimized to enhance this effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the semiconductor device operates in on-state, then current conduction is achieved, but carrier accumulation occurs in the n-type cathode region increasing switching loss
Solution Approach 1:
The second electrode is divided into two distinct parts: a first part that contacts the p-type anode region to extract holes, and a second part that contacts the n-type cathode region. This segmentation allows independent optimization of hole extraction and carrier management functions, reducing switching loss while maintaining current conduction capability
Solution Approach 2:
The first part of the second electrode acts as an intermediary structure between the p-type anode region and the external circuit. By providing a dedicated hole extraction path through this intermediary electrode part, carriers are removed from the n-type cathode region more efficiently, reducing switching loss without compromising power conduction
2Loss of energy
If the first part of the second electrode is made longer to improve hole extraction, then carrier accumulation is reduced, but device complexity increases
Solution Approach 1:
The electrode structure implements local quality by making the first part of the second electrode longer specifically in the region where hole extraction is needed from the p-type anode region. This localized structural variation optimizes carrier extraction performance without unnecessarily complicating the overall device structure
Solution Approach 2:
The second electrode exhibits asymmetric design where the first part has a greater length than the second part. This asymmetry is strategically applied to match the non-uniform carrier distribution and extraction requirements in different regions of the semiconductor device, improving hole extraction efficiency while maintaining manufacturing feasibility
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 design reduces carrier accumulation in the n-type cathode region, leading to faster switching and lower switching loss in semiconductor devices.
Implementation Method 1
forming a Schottky junction that reduces carrier injection and accumulation in the n-type cathode region
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first electrode, a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type, a third semiconductor region of the second conductivity type, and a second electrode. The third semiconductor region is located on the second semiconductor region, and has a higher second-conductivity-type impurity concentration than the second semiconductor region. The second electrode is located on the third semiconductor region. The second electrode includes a first part and a second part. The first part is located in the second semiconductor region. The second part is positioned on the first part, and contacts the third semiconductor region in a second direction perpendicular to a first direction from the first electrode toward the first semiconductor region. A length of the first part is greater than a length of the second part in the second direction.