SOI Semiconductor Device With Selective Epitaxial Growth
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Solution Overview
Problem
Current semiconductor devices using silicon on insulator (SOI) substrates face challenges in efficiently forming semiconductor elements with varying thicknesses, which affects the performance and integration of different elements on a single substrate, particularly in mobile communication devices where multiple frequency bands and modulation systems are handled.
Innovation Solution
A manufacturing method that involves forming both thin film and thick film semiconductor regions on an SOI substrate, using epitaxial growth to create distinct element regions with different isolation types, allowing for the integration of various semiconductor elements with optimized properties, such as MISFETs for antenna switching, analog, and digital circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single SOI layer thickness is used across the substrate, then manufacturing process is simplified, but different semiconductor elements requiring different thicknesses cannot be formed
Solution Approach 1:
The SOI substrate is divided into multiple regions with different SOI layer thicknesses. A first SOI layer is formed across the entire substrate, then a second SOI layer is formed only in specific thick-film regions through selective epitaxial growth. This segmentation allows different semiconductor elements to have optimized thicknesses while maintaining a unified substrate structure.
Solution Approach 2:
Different regions of the substrate are given different SOI layer thicknesses according to the specific requirements of each semiconductor element. Thin-film regions maintain the original thin SOI layer for low-capacitance elements, while thick-film regions receive additional epitaxial growth for high-voltage elements, achieving local optimization without affecting the entire substrate.
2Reliability
If multiple isolation types are formed across the entire substrate, then all elements benefit from enhanced isolation, but manufacturing complexity and cost increase
Solution Approach 1:
Perfect isolation and partial isolation structures are selectively formed only in regions where they are required. The isolation type and depth are matched to the specific needs of each semiconductor element, avoiding unnecessary isolation complexity in regions where simpler isolation suffices.
Solution Approach 2:
Instead of applying the most rigorous isolation (perfect isolation reaching the box layer) across the entire substrate, the patent applies different isolation depths selectively: perfect isolation in thick-film regions requiring high reliability, and partial isolation in thin-film regions where it is sufficient, thereby reducing overall manufacturing complexity.
3Reliability
If different SOI layer thicknesses are formed for different elements, then each element can be optimized for its specific function, but the manufacturing process becomes more complex
Solution Approach 1:
The first SOI layer is formed across the entire substrate before any thickness differentiation. This preliminary uniform layer provides a consistent foundation, and subsequent selective epitaxial growth of the second SOI layer adds thickness only where needed, simplifying the overall process compared to attempting to form different thicknesses from scratch in each region.
Solution Approach 2:
The SOI layer thickness parameter is changed selectively in different regions through controlled epitaxial growth. By adjusting the growth conditions and duration only in thick-film regions, the patent achieves different thicknesses without changing the fundamental formation process across the entire substrate.
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 approach enables the formation of semiconductor devices with improved properties, such as reduced parasitic capacitance, high voltage resistance, and efficient element isolation, facilitating the integration of multiple functions on a single chip, thereby reducing the area, weight, and power consumption of mobile communication devices.
Implementation Method 1
a second insulating film is formed in the first semiconductor film with a first film thickness in the first isolation region and the second isolation region; forming a third insulating film in the thin film region; forming third semiconductor films over the first semiconductor film with the first film thickness in the third element region and the fourth element region exposed from the third insulating film
Data Source
AI summary
A semiconductor device has a first element region, a second element region, and a first isolation region in a thin film region and a third element region, a fourth element region, and a second isolation region in a thick film region. It is manufactured with step (a) of providing a substrate having a silicon layer formed via an insulating layer, step (b) of forming element isolation insulating films in the silicon layer in the first isolation region and the second isolation region of the substrate step (c) of forming a hard mask in the thin film region, step (d) of forming silicon films over the silicon layer exposed from the hard mask in the third element region and the fourth element region, and step (e) of forming element isolation insulating films between the silicon films in the third element region and the fourth element region.