Semiconductor Structure with Laterally Disposed Layers for FET Mobility
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Solution Overview
Problem
Conventional semiconductor structures can only optimize mobility performance for either N-channel or P-channel field-effect transistors (FETs) due to uniform crystal orientation in doped regions, limiting the simultaneous optimization of both types.
Innovation Solution
A semiconductor structure is fabricated with first, second, and third crystalline semiconductor layers having different crystal orientations, where the second layer is laterally disposed between the first and third layers, allowing for the formation of both N-channel and P-channel FETs with optimized mobility performance by using a solid-phase epitaxial growth process and epitaxial growth techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional semiconductor structure with uniform crystal orientation is used, then the manufacturing process is simple, but the mobility performance can only be optimized for either N-channel or P-channel FETs, not both simultaneously
Solution Approach 1:
The semiconductor structure is divided into multiple doped regions, each with different crystal orientations. Specifically, first doped regions have a first crystal orientation optimized for N-channel FETs, while second doped regions have a second crystal orientation optimized for P-channel FETs. This segmentation allows each region to be independently optimized for its intended transistor type, resolving the contradiction between versatility and complexity.
Solution Approach 2:
Different crystal orientations are assigned to different local regions of the semiconductor structure based on the specific requirements of N-channel and P-channel FETs. The first doped regions possess crystal orientation properties that maximize electron mobility for N-channel devices, while the second doped regions possess crystal orientation properties that maximize hole mobility for P-channel devices. This local quality differentiation enables simultaneous optimization of both transistor types within a single structure.
2Reliability
If different crystal orientations are used in doped regions to optimize mobility for both N-channel and P-channel FETs, then mobility performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The different crystal orientations are established in the doped regions during the initial formation stages of the semiconductor structure, before the FET fabrication processes begin. By preliminarily configuring the crystal orientations in the doped regions, the need for complex in-process orientation changes or additional manufacturing steps is eliminated, thus maintaining ease of manufacture while achieving improved mobility performance.
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 simultaneous optimization of mobility performance for both N-channel and P-channel FETs, enhancing their performance by leveraging different crystal orientations for each type.
Implementation Method 1
The first crystalline semiconductor layer includes a crystallized amorphous region formed on the substrate. The second crystalline semiconductor layer is grown on the substrate and is laterally disposed of the first crystalline semiconductor layer
Data Source
AI summary
A semiconductor structure includes a substrate and first and second crystalline semiconductor layers. The first crystalline semiconductor layer has a first crystal orientation, and includes a crystallized amorphous region formed on the substrate. The second crystalline semiconductor layer is formed on the substrate, is laterally disposed of the first crystalline semiconductor layer, and has a second crystal orientation different from the first crystal orientation. A method of fabricating the semiconductor structure is also disclosed.