Split Gate Oxide Structure for High-Voltage Switching Balance
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Solution Overview
Problem
Existing semiconductor structures face challenges in withstanding high voltages while maintaining electrical performance, as thick gate insulating layers can lead to electrical breakdown and complex manufacturing processes complicate the integration of high and low voltage transistors.
Innovation Solution
A semiconductor structure with separated gate sub-structures, where the sub-gate insulating layers have distinct thicknesses, with a thicker layer closer to the drain region to withstand high voltage and a thinner layer closer to the source region for improved switching current and control, fabricated using the same gate insulation material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thicker gate insulating layer is used to withstand high voltage, then voltage withstanding capability is improved, but switching current and electrical performance deteriorate
Solution Approach 1:
The gate insulating layer is segmented into two separate sub-gate insulating layers with different thicknesses. The first sub-gate insulating layer has a first thickness and the second sub-gate insulating layer has a second thickness greater than the first thickness. This segmentation allows each layer to perform its specific function: the thinner first layer enables good switching current while the thicker second layer provides high voltage withstanding capability.
Solution Approach 2:
Different regions of the gate insulating structure are given different thicknesses to match local requirements. The region closer to the source (first sub-gate insulating layer) has a thinner thickness optimized for switching current, while the region closer to the drain (second sub-gate insulating layer) has a thicker thickness optimized for voltage withstanding capability. This local differentiation resolves the contradiction between uniform thickness requirements.
2Reliability
If different thickness gate insulating layers are used for high and low voltage transistors, then electrical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process segments the gate insulating layer formation into two distinct deposition steps, allowing different thicknesses to be formed for different transistor regions. This segmentation enables customized electrical performance for high and low voltage transistors while maintaining a systematic manufacturing approach.
Solution Approach 2:
The invention changes the thickness parameter of the gate insulating layer in different regions by performing separate deposition processes. The first gate insulating layer is formed with a first thickness and the second gate insulating layer is formed with a second thickness, allowing parameter optimization for different transistor types without requiring complete process redesign.
3Ease of manufacture
If a single thickness gate insulating layer is used, then manufacturing process is simplified, but both high voltage withstanding and switching performance cannot be simultaneously achieved
Solution Approach 1:
The gate insulating layer is segmented into two sub-layers formed by separate deposition processes, enabling simultaneous optimization for both voltage withstanding and switching performance. This segmentation resolves the contradiction by allowing each layer to be optimized for its specific function while maintaining a relatively simple manufacturing process.
Solution Approach 2:
Different regions of the gate insulating structure are given different thicknesses to match local functional requirements. The thinner first sub-gate insulating layer optimizes switching performance while the thicker second sub-gate insulating layer optimizes voltage withstanding capability, achieving local quality optimization without excessive manufacturing complexity.
Data Source
AI summary
A semiconductor structure and a method for fabricating the same are provided. The semiconductor structure includes a substrate, a source region, a drain region and a gate structure. The source region is located in the substrate. The drain region is located in the substrate. The gate structure is disposed on the substrate and located between the source region and the drain region, and includes a first sub-gate structure and a second sub-gate structure. The first sub-gate structure is adjacent to the source region and includes a first sub-gate insulating layer. The second sub-gate structure is adjacent to the drain region and includes a second sub-gate insulating layer. The second sub-gate insulating layer and the first sub-gate insulating layer are separated from each other. The first sub-gate insulating layer has a first thickness, and the second sub-gate insulating layer has a second thickness greater than the first thickness.