Schottky Diode Anode Layout for Better Reverse Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices with a P anode region shielded by an N layer face challenges in enhancing reverse recovery characteristics.
Innovation Solution
The semiconductor device incorporates a first anode region of a first conductivity type in Schottky contact with an anode electrode, a second anode region of a second conductivity type with a lower doping concentration, and a drift region, where the first anode region is spaced from the drift region by the second anode region, with specific doping concentrations and spatial arrangements to optimize depletion layer formation and reduce hole injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P anode region is shielded by an N layer, then reverse recovery characteristics are improved, but leak current and hole injection increase
Solution Approach 1:
The anode region is divided into two distinct parts: a first anode region with higher doping concentration (1E18 to 1E20 cm^-3) that provides low resistance contact, and a second anode region with lower doping concentration (1E15 to 1E17 cm^-3) that forms the Schottky barrier. This segmentation allows each region to fulfill its specific function without compromising the other, resolving the contradiction between low leak current and good electrical contact.
Solution Approach 2:
Different regions of the anode are given different doping concentrations to optimize local properties. The first anode region has high doping concentration for low resistance and high carrier injection, while the second anode region has low doping concentration for forming a wide depletion layer and reducing leak current. This local differentiation of properties allows simultaneous achievement of low leak current and good electrical characteristics.
2Object-generated harmful factors
If the first anode region is placed closer to the drift region, then hole injection is reduced, but electrical contact resistance increases
Solution Approach 1:
The anode structure is segmented into two regions with different doping concentrations positioned at different depths. The first anode region (higher doping) is positioned closer to the drift region to reduce hole injection, while the second anode region (lower doping) is positioned closer to the metal contact to form the Schottky barrier. This spatial segmentation resolves the contradiction between reducing hole injection and maintaining low electrical contact resistance.
Solution Approach 2:
The doping concentration parameter is changed between the two anode regions to achieve different functional properties. The first anode region has higher doping concentration (1E18 to 1E20 cm^-3) for low resistance contact, while the second anode region has lower doping concentration (1E15 to 1E17 cm^-3) for forming the Schottky barrier. This parameter change allows optimization of both hole injection and electrical contact resistance.
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 configuration enhances reverse recovery characteristics by minimizing leak current and hole injection, improving the device's performance under both forward and reverse bias conditions.
Implementation Method 1
a first anode region of a first conductivity type that is in Schottky contact with the anode electrode
Implementation Method 2
the first anode region has a doping concentration lower than or equal to a doping concentration of the second anode region
Data Source
AI summary
There is provided a diode including an anode electrode provided on a side of a front surface of a semiconductor substrate, an interlayer dielectric film disposed between the semiconductor substrate and the anode electrode, a first anode region of a first conductivity type provided on the front surface of the semiconductor substrate, a second anode region of a second conductivity type, which is different from the first conductivity type, provided on the front surface of the semiconductor substrate, a first contact hole provided in the interlayer dielectric film, causing the anode electrode to be in Schottky contact with the first anode region, and a second contact hole provided in the interlayer dielectric film and different from the first contact hole, causing the anode electrode to be in ohmic contact with the second anode region.