MOS device with resistive field plate for realizing conductance modulation field effect and preparation method thereof
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Solution Overview
Problem
High-voltage silicon power devices face a challenge in achieving both high breakdown voltage and low on-resistance due to the contradictory relationship between these two parameters, with existing super junction structures not effectively utilizing dielectric materials with high dielectric constants and semi-insulating material layers.
Innovation Solution
A MOS device with a resistive field plate is introduced, featuring a semi-insulating resistive field plate electrically connected to a trench gate structure and drain structure, which modulates the conductance of the on-state drift region and the distribution of the off-state high-voltage blocking electric field, utilizing modern 2.5-dimensional processing technology for deep trench etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the breakdown voltage of the drift region is increased to withstand higher voltage, then the breakdown voltage is improved, but the on-resistance of the drift region increases significantly
Solution Approach 1:
The drift region is segmented into multiple superjunction cells, each with alternating P-type and N-type columns. This segmentation allows the electric field to be distributed across multiple regions, enabling high breakdown voltage while maintaining low on-resistance through parallel conduction paths.
Solution Approach 2:
Different regions of the drift region are given different doping types (P-type and N-type alternating columns) to create localized charge compensation zones. This local quality variation enables simultaneous achievement of high voltage blocking capability and low resistance through charge balance in each local region.
2Object-affected harmful factors
If traditional super junction structures are used to reduce on-resistance, then the on-resistance is reduced, but the implementation of dielectric materials with high dielectric constant and semi-insulating material layers remains ineffective
Solution Approach 1:
The invention uses composite material structures combining P-type and N-type semiconductor columns with specific doping concentrations. This composite structure creates charge balance at the interfaces, enabling effective superjunction operation that reduces on-resistance while being manufacturable with existing semiconductor processes.
Solution Approach 2:
The invention optimizes parameters including doping concentrations (1e16 to 1e18 atoms/cm³ for P-type, 1e16 to 1e18 atoms/cm³ for N-type), column widths (0.5 to 5 μm), and drift region thickness to achieve the desired balance between breakdown voltage and on-resistance. These parameter changes make the structure effectively manufacturable.
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 reduces on-resistance while maintaining high breakdown voltage, with a 70% to 105% increase in current output capability compared to first-generation PN junction type super junction devices, and enables miniaturization and high-density design suitable for advanced semiconductor devices.
Implementation Method 1
a semi-insulating resistive field plate electrically connected to the trench gate structure and drain, which modulates the conductance of the on-state drift region
Implementation Method 2
distributes the off-state high-voltage blocking electric field
Data Source
AI summary
The MOS device with resistive field plate for realizing conductance modulation field effect in the present invention is based on the existing trench gate MOS device, and a semi-insulating resistive field plate electrically connected to the trench gate structure and the drain structure is added in the drift region, where the trench gate structure can control the on-off of the MOS channel, and the semi-insulating resistive field plate can adjust the doping concentration of the drift region to modulate the conductance of the on-state drift region and the distribution of off-state high-voltage blocking electric field, thus a lower on-resistance can be obtained. In addition, the modern 2.5-dimensional processing technology based on deep trench etching is adopted in the present invention, which is conducive to the miniaturization design and high density design of the structure and is more suitable for the More than Moore (beyond Moore) development of modern integrated semiconductor devices.