Monolithic Schottky Diode Integration in HVIC
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Solution Overview
Problem
Conventional high voltage integrated circuits (HVICs) require external bootstrap and voltage clamping diodes, which increase size and impact performance, and there is a need for monolithically integrated Schottky diodes to improve these characteristics.
Innovation Solution
The integration of monolithic bootstrap Schottky diodes and voltage clamping Schottky diodes within the HVIC, utilizing a semiconductor die with high voltage and low voltage regions isolated by high voltage junction isolation termination, allowing for reduced leakage current and enhanced reverse blocking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external bootstrap diode and voltage clamping diode are used, then the HVIC can achieve basic high voltage switching function, but the device size increases and performance deteriorates
Solution Approach 1:
The patent merges the bootstrap diode and voltage clamping diode functions into a single monolithic Schottky diode structure integrated within the HVIC. This integration eliminates the need for external discrete diodes, reducing device size while maintaining or improving switching performance through optimized internal geometry and material composition.
Solution Approach 2:
The monolithic Schottky diode structure performs multiple functions simultaneously: it operates as a bootstrap diode during switching operations and as a voltage clamping diode during voltage spikes. This multi-functionality is achieved through the diode's inherent Schottky barrier characteristics and its strategic placement within the half-bridge configuration, eliminating the need for separate specialized components.
2Reliability
If external diodes are used for high voltage termination, then basic protection function is provided, but switching speed and overall performance are adversely impacted
Solution Approach 1:
The patent replaces external mechanical/discrete diode components with a monolithic integrated Schottky diode structure fabricated using semiconductor processing techniques. This substitution enables closer physical integration with the switching elements, reducing parasitic inductance and capacitance, thereby improving switching speed while maintaining high voltage blocking capability through the Schottky barrier mechanism.
Solution Approach 2:
The patent utilizes the unique electrical parameters of Schottky diodes—specifically their low forward voltage drop, fast reverse recovery time, and high breakdown voltage characteristics—to optimize the half-bridge performance. By changing from conventional p-n junction diodes to Schottky barrier diodes, the system achieves faster switching speeds and improved efficiency while maintaining robust high voltage blocking 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
This integration enhances the performance of HVICs by reducing size and improving switching speed, while maintaining high voltage blocking capabilities and frequency, thus addressing the limitations of external diodes.
Implementation Method 1
a first Schottky diode integrated in the semiconductor die... configured to prevent reverse current flow
Data Source
AI summary
A Schottky diode includes a cathode terminal in a high voltage region of a semiconductor die, an anode terminal in a low voltage region of the semiconductor die, where the anode terminal and the cathode terminal are separated by a junction isolation termination situated between the high voltage region and the low voltage region. The Schottky diode includes a junction barrier Schottky diode or a trench metal-oxide-semiconductor (MOS) Schottky diode. The junction isolation termination includes pzener rings. The semiconductor die includes a substrate of a first conductivity type, an epitaxial layer of a second conductivity type situated on the substrate, a well region of the second conductivity type situated in the epitaxial layer in the high voltage region, and coupled to the cathode terminal, a Schottky barrier situated on the epitaxial layer in the low voltage region, and coupled to the anode terminal.