Schottky Barrier Diode Graded Doping for BCD Switching
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Solution Overview
Problem
Schottky diodes in BCD technology applications face limitations with lower breakdown voltage and higher leakage current compared to P-N junction diodes, necessitating improvements for high-performance switching applications.
Innovation Solution
The semiconductor device incorporates a Schottky barrier diode structure with a diffused well region, a buried layer, and a poly field plate, optimizing dopant concentrations and ion implantation processes to enhance breakdown voltage and reduce leakage current, while using an epitaxial process to increase forward bias current and reduce lateral fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a Schottky barrier diode is used for high-speed switching applications, then switching speed is improved, but breakdown voltage is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform dopant concentration distribution within the N-type well region. The dopant concentration is higher near the Schottky interface and decreases toward the bulk, which locally optimizes the barrier properties at the interface while maintaining higher breakdown voltage in the bulk region. This graded doping profile allows the device to simultaneously achieve fast switching and high breakdown voltage.
Solution Approach 2:
The patent changes the dopant concentration parameter by introducing a graded profile instead of a uniform distribution. By controlling the dopant concentration to decrease from the interface toward the bulk, the patent optimizes both the Schottky barrier height for fast switching and the depletion region characteristics for high breakdown voltage, resolving the contradiction between switching speed and breakdown voltage.
2Loss of time
If a Schottky barrier diode is used for high-speed switching, then reverse recovery time is reduced, but leakage current increases
Solution Approach 1:
The graded dopant concentration profile creates local quality variations that reduce leakage current by forming a more effective depletion region. The higher dopant concentration near the interface maintains good Schottky contact properties for fast switching, while the decreasing concentration toward the bulk reduces thermally generated carrier leakage, thus resolving the contradiction between reverse recovery time and leakage current.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the dopant concentration gradient before device operation. This graded profile is established during manufacturing to proactively reduce leakage current pathways while maintaining fast switching characteristics, preventing the leakage issue before it occurs during device operation.
3Power
If dopant concentration in the N-type well is increased to increase forward bias current, then forward current is improved, but breakdown voltage decreases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through a graded dopant concentration profile. The dopant concentration is locally high near the Schottky interface to ensure good electrical contact and sufficient forward bias current, while gradually decreasing toward the bulk region to maintain high breakdown voltage. This spatial variation in dopant concentration allows both requirements to be satisfied simultaneously.
Solution Approach 2:
The patent transitions from a uniform one-dimensional dopant concentration to a graded one-dimensional profile, effectively adding the dimension of concentration gradient. This dimensional change in the dopant distribution allows the device to optimize forward bias current at the interface while preserving breakdown voltage in the bulk, resolving the power-strength contradiction.
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 design effectively increases breakdown voltage, reduces leakage current, and enhances forward bias current, improving the performance of Schottky diodes in BCD technology by optimizing the structure and process parameters.
Implementation Method 1
a Schottky barrier diode is formed between the silicide and the N-type diffused well region
Implementation Method 2
optimizing dopant concentrations and ion implantation processes
Data Source
AI summary
A semiconductor device includes a first N-type deep well region and a second N-type deep well region formed in a substrate, an N-type diffused well region formed between the first N-type deep well region and the second N-type deep well region, wherein a concentration of the N-type diffused well region is less than a concentration of the first N-type deep well region or the second N-type deep well region, a first P-type well region formed in the first N-type deep well region, a second P-type well region formed in the N-type diffused well region, an insulating film formed to be in contact with the first P-type well region, and a silicide formed on the N-type diffused well region, such that a Schottky barrier diode is formed between the silicide and the N-type diffused well.