M-Type HV MOSFET Breakdown Voltage via Dopant Control
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Solution Overview
Problem
Conventional M-type high voltage MOSFET devices have a lower breakdown voltage due to round corners, leading to impaired voltage-withstanding capability and reduced conduction current, making it difficult to integrate them with other shapes on the same integrated circuit without compromising overall performance.
Innovation Solution
A high voltage MOSFET device design with a substrate, deep well region, source/body region, drain region, and gate structure, where the dopant doses in the boundary and middle sites of the deep well region are controlled to maintain a percentage difference of less than or equal to 5%, using specific implantation masks to ensure uniform dopant distribution and enhance breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the radius of the HV MOSFET device is increased to increase the conduction current, then the conduction current is improved, but the area of the device increases
Solution Approach 1:
The patent employs an M-type configuration with curved boundaries and rounded corners in the deep well region, transforming the conventional circular layout into an optimized curved geometry that increases effective channel width without proportionally increasing device area, thereby improving conduction current density
2Power
If the M-type HV MOSFET device is used to achieve higher conduction current, then the conduction current is improved, but the breakdown voltage is lower than circular and race-track devices
Solution Approach 1:
The patent applies non-uniform doping concentrations within the deep well region, with specifically engineered dopant doses at boundary sites versus middle sites, creating localized electrical field distributions that suppress premature breakdown while preserving the high conduction current capability of the M-type structure
Solution Approach 2:
The patent modifies the electrical parameters by controlling the ratio of dopant doses between first doped regions and deep well region sites, with specific percentage difference constraints (≤5%) to optimize the balance between conduction current and breakdown voltage characteristics
3Ease of manufacture
If conventional M-type HV MOSFET device with round corners is used, then the manufacturing is simplified, but the electric field concentration at round corners impairs voltage-withstanding capability
Solution Approach 1:
The patent implements spatially varying dopant concentrations within the deep well region, with different dopant doses at boundary sites compared to middle sites, creating localized field control that compensates for the electric field concentration effect of rounded corners while maintaining manufacturing simplicity
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 controlled dopant distribution effectively increases the breakdown voltage of the M-type HV MOSFET device, minimizing degradation and improving overall performance, while allowing for integration with other shapes on the same integrated circuit.
Implementation Method 1
using specific implantation masks to ensure uniform dopant distribution and enhance breakdown voltage
Data Source
AI summary
A HV MOSFET device includes a substrate, a deep well region, a source/body region, a drain region, a gate structure, and a first doped region. The deep well region includes a boundary site and a middle site. The source/body region is formed in the deep well region and defines a channel region. The first doped region is formed in the deep well region and disposed under the gate structure, and having the first conductivity type. There is a first ratio between a dopant dose of the first doped region and a dopant dose of the boundary site of the deep well region. There is a second ratio between a dopant dose of the first doped region and a dopant dose of the middle site of the deep well region. A percentage difference between the first ratio and the second ratio is smaller than or equal to 5%.