High Voltage DMOS With Selective Doping For Breakdown Voltage
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Solution Overview
Problem
High voltage DMOS devices have limited breakdown voltage and application range due to inflexibility in ion implantation parameters, requiring additional manufacturing steps to integrate with low voltage devices, which increases costs.
Innovation Solution
A high voltage device with a first low concentration doped region beneath the gate, having a lower impurity concentration than the surrounding well, formed using the same lithography and ion implantation process steps as the well, allowing for increased breakdown voltage without additional manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional lithography and ion implantation processes are used to provide different ion implantation parameters for high voltage devices, then breakdown voltage increases, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent introduces a selectively doped region with different impurity concentration within the device region, creating local quality variation. This allows the high voltage device to have optimized electrical characteristics in specific areas without requiring separate manufacturing processes, thereby increasing breakdown voltage while maintaining process simplicity
Solution Approach 2:
The patent changes the impurity concentration parameter by forming a selectively doped region with different doping levels compared to the surrounding well region. This parameter change enables the high voltage device to achieve higher breakdown voltage using the same manufacturing process, avoiding additional lithography and ion implantation steps
2Reliability
If additional lithography and ion implantation processes are used to provide different ion implantation parameters for high voltage devices, then breakdown voltage increases, but manufacturing cost increases
Solution Approach 1:
The patent merges the formation of the selectively doped region with the existing well formation process by using the same lithography and ion implantation steps. This consolidation allows both the high voltage device with optimized doping and the standard devices to be manufactured simultaneously, increasing breakdown voltage without additional manufacturing costs
3Ease of manufacture
If high voltage devices and low voltage devices use the same manufacturing process steps, then manufacturing cost decreases, but flexibility in ion implantation parameters decreases
Solution Approach 1:
The patent segments the device region into a selectively doped region and a non-selectively doped region within the same substrate. This segmentation allows different ion implantation parameters to be applied to different device types using the same manufacturing process, maintaining both cost-effectiveness and parameter flexibility for high voltage and low voltage devices
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
Enhances breakdown voltage of high voltage devices, enabling broader application ranges while maintaining cost-effectiveness by integrating with low voltage devices using common manufacturing processes.
Implementation Method 1
the ion implantation implants N-type impurities to the defined regions in the form of accelerated ions
Data Source
AI summary
The present invention discloses a high voltage device and a manufacturing method thereof. The high voltage device is formed in a well of a substrate. The high voltage device includes: a field oxide region; a gate, which is formed on a surface of the substrate, and part of the gate is located above the field oxide region; a source and a drain, which are formed at two sides of the gate respectively; and a first low concentration doped region, which is formed beneath the gate and has an impurity concentration which is lower than that of the well surrounded, wherein from top view, the first low concentration doped region has an area within the gate and not larger than an area of the gate, and the first low concentration doped region has a depth which is deeper than that of the source and drain.