Monolithically Integrated Active Snubber for Voltage Ringing
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Solution Overview
Problem
Semiconductor devices with extended drain MOS transistors experience undesirable voltage oscillations, known as ringing, which can be challenging to dampen without increasing fabrication cost and complexity by integrating a snubber.
Innovation Solution
An integrated snubber is formed within the semiconductor device by creating a snubber capacitor over the extended drain of the MOS transistor and a snubber resistor connected in series between the capacitor plate and the source of the MOS transistor, allowing for concurrent formation with other device elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a snubber is added to dampen voltage oscillations, then voltage ringing is reduced, but fabrication cost and device complexity increase
Solution Approach 1:
The snubber circuit is merged with the MOS transistor structure by integrating the snubber capacitor between the drain diffusion region and substrate, and the snubber resistor in the source region, eliminating the need for separate external snubber components and reducing overall device complexity
Solution Approach 2:
The extended drain structure serves multiple functions: it provides the main current conduction path for the MOS transistor while simultaneously hosting the snubber capacitor and resistor elements, allowing a single structural feature to fulfill both power switching and voltage oscillation damping functions
2Object-affected harmful factors
If a snubber is added to dampen voltage oscillations, then voltage ringing is reduced, but fabrication cost increases
Solution Approach 1:
The snubber components are combined with standard MOS transistor fabrication steps, where the snubber capacitor is formed using the drain diffusion region and substrate, and the snubber resistor is created during source region processing, allowing simultaneous fabrication without additional manufacturing steps or materials
Solution Approach 2:
The drain drift region and extended drain structure automatically provide the capacitive and resistive elements needed for the snubber circuit, eliminating the need for separate component fabrication and reducing manufacturing complexity and cost
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 integrated snubber effectively dampens voltage oscillations, improving the performance of semiconductor devices without significantly increasing fabrication costs or complexity.
Implementation Method 1
forming a snubber capacitor including a capacitor dielectric layer and capacitor plate over the extended drain
Implementation Method 2
A snubber resistor is formed over a gate of the MOS transistor and connected in series between the capacitor plate and a source of the MOS transistor
Data Source
AI summary
A semiconductor device containing an extended drain MOS transistor with an integrated snubber formed by forming a drain drift region of the MOS transistor, forming a snubber capacitor including a capacitor dielectric layer and capacitor plate over the extended drain, and forming a snubber resistor over a gate of the MOS transistor so that the resistor is connected in series between the capacitor plate and a source of the MOS transistor.