Bootstrap Schottky Diode Guard Ring Layout for Leakage Control
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Solution Overview
Problem
Bootstrap Schottky diodes in high voltage semiconductor devices experience significant leakage current and are vulnerable to high voltages, compromising their reliability.
Innovation Solution
The semiconductor device incorporates a deep n-type well, source and drain regions, a Schottky diode with an anode and cathode electrodes, and p-type guard rings, along with field plates and trenches, to reduce leakage current and protect the diode from high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a Schottky diode is used as a bootstrap diode, then the diode can operate at high voltages, but a large amount of leakage current is generated in the substrate direction
Solution Approach 1:
A deep n-type well is introduced as an intermediary structure between the Schottky diode and the substrate. This deep n-type well acts as a mediator that captures and redirects leakage current away from the substrate, thereby reducing substrate-directed leakage while maintaining the diode's high voltage operation capability
Solution Approach 2:
The substrate structure is segmented by introducing a deep n-type well that divides the current flow path. This segmentation separates the leakage current into different directional paths, preventing it from flowing directly into the substrate while allowing the Schottky diode to maintain its high voltage blocking capability
2Adaptability or versatility
If the bootstrap diode is exposed to high voltage, then it can function in high voltage circuits, but the diode becomes vulnerable to high voltage damage
Solution Approach 1:
A p-type guard ring structure is positioned around the Schottky diode to provide beforehand cushioning against high voltage stress. This guard ring creates a protective field that cushions the diode from direct high voltage exposure, preventing breakdown while allowing the device to function in high voltage circuits
Solution Approach 2:
The p-type guard ring structure performs preliminary anti-action by creating an opposing electric field that counteracts the high voltage stress before it can damage the Schottky diode. This preliminary protective action prevents high voltage breakdown while maintaining circuit functionality
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 design effectively minimizes leakage current and enhances the bootstrap Schottky diode's resilience to high voltages, ensuring reliable operation of the semiconductor device.
Implementation Method 1
a Schottky barrier formed on the first PW and the second PW and connected to the anode electrode
Implementation Method 2
a first p-type guard ring surrounding the Schottky diode, the first p-type guard ring comprising a first p-type buried layer (PBL) and a first deep p-type well (DPW) formed on the first PBL
Data Source
AI summary
A semiconductor device includes a deep n-type well (DNW) formed in a junction termination region, a source region and a drain region formed in the DNW, a source electrode electrically connected to the source region, a drain electrode electrically connected to the drain region, an anode electrode formed in a Schottky diode, a cathode electrode electrically connected to the source electrode and a first p-type guard ring surrounding the Schottky diode, the first p-type guard ring including a first p-type buried layer (PBL) and a first deep p-type well (DPW) formed on the first PBL. The first PBL extends further towards the junction termination region than the first DPW.