High-Voltage Schottky Diode With P-Type Well Region
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Solution Overview
Problem
Conventional Schottky diodes cannot withstand high voltages, making them unsuitable for use as bootstrap diodes in high-voltage integrated circuits, which necessitates the use of external discrete devices, increasing design complexity and cost.
Innovation Solution
A high-voltage Schottky diode is designed with a P-type substrate, N-type buried layers, epitaxial layers, and P-type well regions to enhance voltage withstand and reduce leakage, allowing integration into high-voltage integrated circuits and enabling fast recovery characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional Schottky diode is used, then fast recovery characteristic is achieved, but high voltage withstanding capability is lost
Solution Approach 1:
The diode structure is segmented into multiple functional regions including drift region, depletion region, and high-voltage blocking region. Each region is independently optimized for its specific function, allowing the overall device to achieve both fast recovery and high voltage withstanding capabilities simultaneously
Solution Approach 2:
Different regions of the diode are doped with different concentrations and types of impurities to create locally optimized properties. The drift region has lower doping for high voltage, while the contact region has higher doping for fast carrier extraction, achieving both fast recovery and high voltage capability
2Strength
If an external discrete diode is used to achieve high voltage withstanding, then voltage blocking capability is improved, but device complexity and design complexity increase
Solution Approach 1:
The high-voltage Schottky diode integrates multiple functions that were previously requiring separate discrete components into a single monolithic device structure, eliminating the need for external discrete diodes and reducing overall system complexity while maintaining high voltage capability
Solution Approach 2:
The diode structure is designed to perform multiple functions including high voltage blocking, fast recovery, and integration with CMOS circuits simultaneously, making it a universal component that replaces both the Schottky diode and the external high-voltage protection components
3Strength
If an external discrete diode is used, then high voltage bootstrap function is achieved, but manufacturing cost increases
Solution Approach 1:
The high-voltage Schottky diode is manufactured using standard CMOS fabrication processes, merging the diode production with the existing semiconductor manufacturing line. This eliminates the need for separate discrete component assembly and reduces overall manufacturing cost while achieving high voltage capability
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-voltage Schottky diode can be used as a bootstrap diode, simplifying circuit design, reducing debugging complexity, and lowering the cost of high-voltage integrated circuits by integrating the diode directly into the circuit.
Implementation Method 1
a first P-type well region located on a surface of the second N-type buried layer and surrounding the cathode region configured to protect an edge of the Schottky diode, prevent leakage, and improve withstand-voltage
Implementation Method 2
The common Schottky diode has a characteristic of fast switching, which means it can recover quickly
Data Source
AI summary
A high-voltage Schottky diode and a manufacturing method thereof are disclosed in the present disclosure. The diode includes: a P-type substrate and two N-type buried layers, a first N-type buried layer is located below a cathode lead-out area, and a second N-type buried layer is located below a cathode region; an epitaxial layer; two N-type well regions located on the epitaxial layer, a first N-type well region is a lateral drift region and it is provided with a cathode lead-out region, and a second N-type well region is located on the second N-type buried layer and it is a cathode region; a first P-type well region located on the second N-type buried layer and surrounding the cathode region; a field oxide isolation region located on the lateral drift region; an anode located on the cathode region and a cathode located on the surface of the cathode lead-out region.