High-Voltage Diode Drift Ring for Breakdown Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional high-voltage diodes experience breakdown at the junction between the n+ doping region and the field oxide layer, leading to a shift in breakdown voltage over time, compromising the stability and reliability of the device.
Innovation Solution
Incorporating a conductive n-type drift ring between the n+ doping region and the field oxide layer, or directly under it, to redirect current flow and prevent surface damage, while maintaining the existing fabrication process without additional masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional HV diode structure with n+ doping region and field oxide layer is used, then the device can provide high breakdown voltage protection, but breakdown occurs at the junction between n+ doping region and field oxide layer after long period of operation causing breakdown voltage shift
Solution Approach 1:
An n-type drift ring is introduced as an intermediary structure between the n+ doping region and the field oxide layer. This drift ring acts as a mediator that redistributes the electric field and current density, preventing direct stress concentration at the problematic junction interface. The drift ring with its specific doping concentration and geometric configuration serves as a buffer zone that maintains electrical stability over extended operational periods.
Solution Approach 2:
The patent applies local quality by creating a region with distinct doping characteristics (n-type drift ring with specific concentration profile) at the critical interface zone between the n+ doping region and field oxide layer. This localized modification of material properties addresses the specific stress and field distribution issues at the junction without altering the overall device structure, thereby preventing breakdown while maintaining high breakdown voltage performance.
2Ease of manufacture
If the n+ doping region is directly surrounded by field oxide layer, then the fabrication process is simple, but surface damage occurs at the junction after long term operation
Solution Approach 1:
The n-type drift ring serves as an intermediary layer that protects the surface junction area from harmful electrical stress and degradation. By placing this drift ring between the n+ doping region and the field oxide layer, the patent creates a protective buffer that prevents surface damage accumulation during operation, thereby extending device lifespan without significantly complicating the fabrication process.
Solution Approach 2:
The drift ring is formed as part of the standard fabrication sequence using existing process steps. The preliminary formation of this protective structure during manufacturing prepares the device to resist surface damage before operational stress occurs, preventing degradation rather than repairing it later.
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 n-type drift ring stabilizes the breakdown voltage by distributing current into the substrate, preventing surface damage and enhancing the long-term reliability of the high-voltage diode structure.
Implementation Method 1
The n-type drift ring stabilizes the breakdown voltage by distributing current into the substrate
Data Source
AI summary
A high-voltage semiconductor device is disclosed. The HV semiconductor device includes: a substrate; a well of first conductive type disposed in the substrate; a first doping region of second conductive type disposed in the p-well; a first isolation structure disposed in the well of first conductive type and surrounding the first doping region of second conductive type; and a first drift ring of second conductive type disposed between the first doping region of second conductive type and the first isolation structure.