LDMOS Metal Field Plate Extension for Surface Field Reduction
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Solution Overview
Problem
Existing LDMOS devices face challenges in achieving high breakdown voltage and reducing surface electric fields, which are crucial for efficient operation in high-power applications such as RF power amplifiers.
Innovation Solution
The introduction of a metal field plate extension from the source side to the drain side of the LDMOS device, which connects to contacts extending into an isolation structure, helps to deplete the drift region, reduce surface electric fields, and increase breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDMOS device structure is used, then device complexity is low, but breakdown voltage is insufficient and surface electric fields are high
Solution Approach 1:
The device is segmented into distinct regions including drift region, isolation structure, source region, and drain region. The metal field plate extension is segmented to extend into the isolation structure, creating separate functional zones that collectively achieve higher breakdown voltage while maintaining manageable complexity through modular design
Solution Approach 2:
The metal field plate extension transitions from a planar configuration to a three-dimensional structure by extending vertically into the isolation structure. This dimensional change allows the field plate to interact with the drift region more effectively, enhancing breakdown voltage through improved electric field management in the vertical dimension
2Object-affected harmful factors
If conventional LDMOS device structure is used, then manufacturing process is simple, but surface electric fields are high
Solution Approach 1:
The isolation structure serves as an intermediary element between the metal field plate extension and the drift region. By extending the field plate into this intermediate isolation structure, the design effectively manages surface electric fields through the mediator's presence, while the isolation structure itself is formed using standard semiconductor manufacturing techniques
Solution Approach 2:
The design changes the geometric parameters of the metal field plate by extending it into the isolation structure. This parameter modification (increasing the field plate's extent into the isolation region) directly reduces surface electric field strength, while the manufacturing process remains compatible with existing semiconductor fabrication capabilities
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 solution effectively enhances the breakdown voltage and reduces surface electric fields, thereby improving the transconductance, on-resistance, and overall performance of the LDMOS devices.
Implementation Method 1
the metal field plate extension on the drain side connects to contacts extending into an isolation structure. Advantageously, the metal field plate extension will deplete a drift region, reduce a surface electric field and increase breakdown voltage
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to devices with a metal field plate extension and methods of manufacture. The structure includes: a gate structure over a semiconductor substrate; a drift region under the gate structure; a source region adjacent to the gate structure; a drain region in the drift region; a isolation structure within the drift region; and a contact extending from the source region and into the isolation structure within the drift region.