Ultra-high Voltage Device Partial Dopant Implantation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultra-high voltage devices experience reliability issues due to the hot carrier injection (HCI) effect caused by a strong electric field under thin gate oxides, leading to device deterioration, and conventional dopant implantation increases on-resistance (Rds-on).
Innovation Solution
A partial dopant implantation in the accumulation region with a dopant of opposite conductivity to the second well zone is used, reducing the electric field strength and avoiding HCI, while maintaining a distinct implant type from conventional blanket implantation, applied in semiconductor structures with field oxide or shallow trench isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thin gate oxide is used to reduce voltage requirements, then device cost is reduced, but electric field strength underneath the bird's beak increases causing hot carrier injection
Solution Approach 1:
The patent applies local quality by implanting dopants selectively in specific regions (accumulation region and bird's beak area) rather than uniformly across the entire device. This localized doping approach modifies the electric field distribution specifically where hot carrier injection occurs, without affecting other device regions, thus maintaining reliability while using thin gate oxide.
Solution Approach 2:
The patent changes the doping concentration parameter in the accumulation region and bird's beak area to optimize electric field distribution. By adjusting dopant concentration locally, the electric field strength is reduced in critical areas, preventing hot carrier injection while maintaining the thin gate oxide structure for cost-effectiveness.
2Reliability
If blanket implantation of dopants is performed to reduce hot carrier injection, then device reliability is improved, but on-resistance increases substantially
Solution Approach 1:
The patent applies local quality by implanting dopants selectively in specific regions (accumulation region and bird's beak area) rather than uniformly across the entire device. This localized doping approach modifies the electric field distribution specifically where hot carrier injection occurs, without affecting other device regions, thus maintaining reliability while using thin gate oxide.
Solution Approach 2:
The patent applies partial action by implanting dopants only in the necessary regions (accumulation region and bird's beak area) rather than performing blanket implantation across the entire device. This partial doping approach provides sufficient protection against hot carrier injection while avoiding the excessive on-resistance increase that would result from uniform doping throughout the device.
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 approach effectively reduces the HCI effect and on-resistance (Rds-on) by selectively implanting dopants in the accumulation region, enhancing the reliability of ultra-high voltage devices and maintaining device performance.
Implementation Method 1
only a part of the accumulation region is implanted with a dopant to form an implant region therein
Implementation Method 2
carriers are injected into the gate oxide due to formation of a strong electric field underneath the bird's beak, resulting in deterioration of the characteristics of the device, and generating the so-called hot carrier injection (HCI) effect
Data Source
AI summary
An ultra-high voltage device is provided. The ultra-high voltage device includes a substrate, a first well zone formed in the substrate, a second well zone having a surface formed in the substrate adjacent to the first well zone, a gate oxide formed on the first well zone and the second well zone of the substrate, a gate formed on the gate oxide, a channel formed in the first well zone underneath the gate oxide, an accumulation region formed in the second well zone underneath the gate oxide adjacent to the channel, wherein only a part of the accumulation region is implanted with a dopant to form an implant region therein, and an insulation region formed on the surface of the second well zone of the substrate adjacent to the accumulation region, wherein a boundary is formed between the insulation region and the accumulation region.