Buried Electrode Lateral MOS Transistor ON-Resistance
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Solution Overview
Problem
Existing semiconductor devices with lateral MOS transistors face challenges in improving ON-breakdown voltage and ON-resistance, which are critical for high-pressure resistance and efficient operation.
Innovation Solution
The semiconductor device incorporates a buried electrode formed in the isolation insulating film between the drain and gate electrodes, with a buried part extending from the surface to a depth thinner than the isolation film thickness, enhancing the electric field distribution and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional lateral MOS transistor structure is used, then the device can operate with simple structure, but the ON-breakdown voltage is limited and ON-resistance cannot be sufficiently reduced
Solution Approach 1:
The isolation insulating film is segmented by forming a buried electrode within it, dividing the insulating film into upper and lower portions. This segmentation allows the buried electrode to independently control the electric field distribution in the drift region, thereby improving ON-breakdown voltage without requiring complete structural redesign
Solution Approach 2:
The buried electrode acts as an intermediary element between the drain electrode and the channel formation region. By applying an independent voltage to the buried electrode, the electric field distribution can be optimized, which improves ON-breakdown voltage and reduces ON-resistance without directly modifying the gate or drain structures
2Reliability
If the isolation insulating film thickness is increased to improve breakdown voltage, then higher breakdown voltage is achieved, but the manufacturing process becomes more difficult and cost increases
Solution Approach 1:
Instead of uniformly increasing the isolation insulating film thickness throughout the structure, the invention applies a localized solution by forming a buried electrode at a specific position within the isolation insulating film. This allows breakdown voltage improvement without increasing overall film thickness, maintaining manufacturing feasibility
Solution Approach 2:
The invention changes the electrical parameters by introducing a可控 voltage to the buried electrode, which dynamically adjusts the electric field distribution. This allows optimization of breakdown voltage through voltage control rather than through physical dimension changes that would increase manufacturing difficulty
Data Source
AI summary
An object of the present invention is to further improve electric characteristics such as ON-resistance or an ON-breakdown voltage in a semiconductor device having a lateral MOS transistor.In a semiconductor device having a lateral MOS transistor, a buried electrode is formed at a part of an isolation insulating film located between a drain region and a gate electrode. The buried electrode includes a buried part. The buried part is formed from the surface of the isolation insulating film up to a depth corresponding to a thickness thinner than that of the isolation insulating film. The buried electrode is electrically coupled to the drain region.