Lateral Power Diode Self-Biasing Electrodes Field Control
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Solution Overview
Problem
Conventional lateral semiconductor power devices face limitations in achieving higher blocking capability and lower on-resistance due to competing goals, with doping concentration and depth of the lightly doped drain region being severely limited by transistor breakdown voltage.
Innovation Solution
Integration of self-biasing electrodes in lateral power devices, which alter the electric field distribution in the blocking layer, allowing for higher doping concentration or improved blocking capability for the same on-resistance, achieved through trenches with dielectric layers and conductive electrodes in the drift region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the doping concentration and depth of the lightly doped drain region are increased to reduce on-resistance, then the on-resistance decreases, but the blocking capability deteriorates due to transistor breakdown voltage limitations
Solution Approach 1:
Self-biasing electrodes are introduced as intermediary elements between the drain region and the drift region. These electrodes create localized electric field modifications that enable higher doping concentrations in the LDD region without proportionally increasing the breakdown voltage, thus mediating between the conflicting requirements of low on-resistance and high blocking capability
Solution Approach 2:
The invention changes the electrical parameters of the device by introducing self-biasing electrodes that modify the electric field distribution in the drift region. This allows the LDD region to be more heavily doped and extended deeper while maintaining acceptable breakdown voltage characteristics, effectively changing the operating parameters to resolve the contradiction
2Ease of manufacture
If the doping concentration of the lightly doped drain region is increased to improve on-resistance, then the on-resistance decreases, but the breakdown voltage deteriorates
Solution Approach 1:
Self-biasing electrodes create localized regions of modified electric field strength and distribution. The electrodes are positioned to create strong local fields near the drain that prevent premature breakdown, while allowing higher doping concentrations in the LDD region without uniformly compromising the breakdown voltage across the entire device structure
3Ease of manufacture
If the depth of the lightly doped drain region is extended to reduce on-resistance, then the on-resistance decreases, but the blocking capability deteriorates due to breakdown voltage limitations
Solution Approach 1:
Self-biasing electrodes serve as intermediary structures that enable deeper LDD region extension. The electrodes modify the electric field distribution to accommodate increased LDD depth without proportionally reducing the breakdown voltage, thus mediating between the need for low on-resistance (requiring deep LDD) and high blocking capability
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 integration results in a significant improvement of breakdown voltage and reduction in on-resistance, enhancing the overall performance of lateral power devices such as MOSFETs, IGBTs, diodes, and schottky diodes.
Implementation Method 1
self-biasing electrodes integrated therein... which alter the electric field distribution in the blocking layer
Data Source
AI summary
A schottky diode includes a drift region of a first conductivity type and a lightly doped silicon region of the first conductivity type in the drift region. A conductor layer is over and in contact with the lightly doped silicon region to form a schottky contact with the lightly doped silicon region. A highly doped silicon region of the first conductivity type is in the drift region and is laterally spaced from the lightly doped silicon region such that upon biasing the schottky diode in a conducting state, a current flows laterally between the lightly doped silicon region and the highly doped silicon region through the drift region. A plurality of trenches extend into the drift region perpendicular to the current flow. Each trench has a dielectric layer lining at least a portion of the trench sidewalls and at least one conductive electrode.