Localized SOI Semiconductor Structure for Latch-Up and Connection Flexibility
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Solution Overview
Problem
Traditional bulk semiconductor devices face challenges in shrinking integrated circuit size due to latch-up design requirements, while SOI devices lack flexibility in electrical connections to the semiconductor layer underneath the silicon oxide layer, limiting their application.
Innovation Solution
A semiconductor structure is developed with a bulk substrate and a selective localized SOI substrate, featuring an epitaxy layer, dielectric layer, and silicon layer, where the epitaxy layer is extended upward and the dielectric layer contacts the semiconductor substrate, allowing for localized isolation and flexible device configuration, enabling reduced latch-up design size and enhanced device flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bulk devices are used, then latch-up design can avoid parasitic bipolar device formation, but the planar area increases due to larger N+ to P+ spacing requirements
Solution Approach 1:
The substrate is segmented into bulk substrate regions and SOI substrate regions, allowing different device types to be formed in different areas. This enables the circuit to benefit from both bulk device stability and SOI device compactness without requiring the entire chip to use bulk devices with their large latch-up spacing.
Solution Approach 2:
Different substrate types are used in different local regions: bulk substrate where latch-up prevention is critical and SOI substrate where area reduction is prioritized. This local differentiation allows the design to optimize for reliability in specific areas while minimizing overall planar area.
2Reliability
If entire SOI wafer is used, then parasitic capacitance is reduced and latch-up concern is eliminated, but electrical connection to the semiconductor layer underneath the silicon oxide layer becomes inflexible
Solution Approach 1:
The SOI substrate is used selectively in specific regions rather than across the entire wafer. This segmentation allows areas requiring electrical connection to the underlying layer to use bulk substrate, while areas benefiting from reduced parasitic capacitance use SOI substrate.
Solution Approach 2:
The structure provides different substrate qualities in different locations: SOI substrate where low parasitic capacitance is needed and bulk substrate where electrical connection flexibility is required. This local quality differentiation resolves the contradiction between parasitic capacitance reduction and connection flexibility.
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 effectively reduces latch-up design size and provides flexibility in device design, maintaining the advantages of both bulk and SOI technologies, such as reduced parasitic capacitance and substrate leakage.
Implementation Method 1
The epitaxy layer is disposed on and within the first region of the semiconductor substrate
Data Source
AI summary
A semiconductor structure includes a semiconductor substrate, an epitaxy layer, a dielectric layer, a semiconductor layer, a first semiconductor device and a second semiconductor device. The semiconductor substrate has first region and a second region. The epitaxy layer is disposed on and within the first region of the semiconductor substrate. The dielectric layer is disposed on and within the second region of the semiconductor substrate. The semiconductor layer is disposed on the dielectric layer and within the second region. The first semiconductor device is formed on the epitaxy layer. The second semiconductor device is formed on the semiconductor layer.