Semiconductor Drain Structure for Electric Field Mitigation
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Solution Overview
Problem
Semiconductor devices face challenges in achieving high breakdown voltage, low on-resistance, and high reliability due to strong electric fields that reduce breakdown voltage and increase impact ionization, leading to reliability issues.
Innovation Solution
The semiconductor device incorporates a conductive body between the substrate and drain interconnection, and between the substrate and drain contact plug, to mitigate the electric field intensity and reduce impact ionization by applying potential, along with insulating bodies and conductive polysilicon structures, optimizing the electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor device structure is used, then the device can be manufactured with standard processes, but the breakdown voltage is reduced and reliability is compromised due to strong electric fields causing impact ionization
Solution Approach 1:
An intermediate conductive body is introduced between the drain electrode and the semiconductor substrate. This conductive body serves as a mediator to distribute and reduce the electric field intensity, thereby suppressing impact ionization and improving device reliability without requiring fundamental changes to the manufacturing process
Solution Approach 2:
The electric field distribution parameter is changed by introducing the conductive body with specific conductivity characteristics. This modifies the electric field intensity profile in the drift region, reducing peak fields that cause impact ionization while maintaining the necessary voltage blocking capability
2Reliability
If the electric field intensity is reduced to suppress impact ionization, then reliability improves, but the on-resistance may increase
Solution Approach 1:
The conductive body is positioned specifically in the high-electric-field region near the drain, providing local field reduction where it is most needed. The rest of the device structure maintains its original characteristics, ensuring that on-resistance is not significantly increased while reliability is improved in the critical breakdown region
3Reliability
If additional conductive bodies and insulating bodies are added to optimize electric field distribution, then breakdown voltage and reliability are enhanced, but device complexity increases
Solution Approach 1:
The conductive body serves multiple functions simultaneously: it acts as an electric field distribution element, a potential shielding structure, and can be integrated with existing drain electrode patterns. This multi-functionality reduces the need for additional separate structures, limiting the increase in device complexity while achieving enhanced breakdown voltage and reliability
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 configuration results in a semiconductor device with enhanced breakdown voltage and reliability by reducing electric field intensity and impact ionization, as demonstrated through simulation comparisons with devices lacking these features.
Implementation Method 1
mitigate the electric field intensity and reduce impact ionization by applying potential
Data Source
AI summary
According to one embodiment, a semiconductor device includes: a semiconductor substrate; a first well of a first conductivity type in a surface region that comprises a surface of the semiconductor substrate; a first impurity region of a second conductivity type in a region of a surface of the first well; a second impurity region of the second conductivity type, a portion of the first well being located between the second impurity region and the first impurity region in the surface region of the semiconductor substrate; a first insulating body on the surface of the semiconductor substrate; a gate electrode extending over part of the first well and part of the second impurity region on the first insulating body; a second insulating body extending on an upper surface of the gate electrode and over a region above the second impurity region; and a first conductive body on the second insulating body.