SiC Schottky Diode PN Junction for High Breakdown Voltage
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Solution Overview
Problem
Conventional silicon carbide (SiC) diodes face challenges with high turn-on voltage and slow switching speed, limiting their ability to meet the demands of high breakdown voltage and high current density required for large and high-capacity power semiconductor devices.
Innovation Solution
A semiconductor device structure is developed with an n-type layer, a p+ type region, and a p− type region, where the side surfaces of the p+ and n-type layers are in contact, and the ion doping concentration of the p+ type region is higher than that of the p− type region, along with a Schottky metal and ohmic metal configuration, forming a PN junction that maximizes electric field distribution and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a SiC Schottky Barrier Diode (SBD) structure is used, then high current density is achieved, but leakage current characteristic deteriorates
Solution Approach 1:
The patent merges the Schottky Barrier Diode structure with a PN junction by introducing a p-type region adjacent to the Schottky junction. This combination allows the device to achieve both high current density (from the Schottky barrier) and improved leakage current characteristic (from the PN junction's inherent blocking capability).
Solution Approach 2:
The patent creates a composite semiconductor structure combining n-type drift layer, p-type region, and Schottky metal contact. This composite structure leverages the advantageous properties of each material layer to simultaneously achieve high current density and low leakage current, resolving the technical contradiction between these two parameters.
2Strength
If a bipolar element structure is used, then high breakdown voltage is achieved, but switching speed deteriorates
Solution Approach 1:
The patent applies local quality by creating a localized p-type region only where needed adjacent to the Schottky junction, rather than using a full bipolar structure. This localized approach provides high breakdown voltage at the junction interface while maintaining fast switching characteristics in the bulk device, avoiding the slow switching inherent in conventional bipolar elements.
3Strength
If the thickness of the p+ type region is increased, then breakdown voltage is improved, but manufacturing precision requirement increases
Solution Approach 1:
The patent optimizes the thickness parameter of the p-type region to a specific range (0.1-1.0 μm) that balances breakdown voltage performance with manufacturing feasibility. By carefully selecting this parameter, the patent achieves high breakdown voltage without requiring extreme manufacturing precision that would be difficult to implement in production.
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 proposed structure significantly increases breakdown voltage by 82% and current density by 52%, while reducing on-resistance and electrical conductive area, enabling improved performance and cost-effectiveness in semiconductor devices.
Implementation Method 1
forming a PN junction that maximizes electric field distribution and breakdown voltage
Implementation Method 2
a Schottky metal and ohmic metal configuration
Implementation Method 3
a Schottky metal and ohmic metal configuration
Data Source
AI summary
A semiconductor device may include: an n type of layer disposed on a first surface of a substrate; a p+ type of region disposed on the first surface of the substrate; a p− type of region disposed at a top portion of the n type of layer; a first electrode disposed on the p+ type of region and the p− type of region; and a second electrode disposed on a second surface of the substrate, wherein the side surface of the p+ type of region and the side surface of the n type of layer are in contact, and the thickness of the p+ type of region is the same as the thickness of the n type of layer and the thickness of the p− type of region.