Strained Silicon Germanium Fin Structures for Carrier Mobility
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Solution Overview
Problem
Conventional semiconductor devices, such as planar FETs, have reached scaling limits, necessitating the development of unconventional geometries like finFETs to continue performance improvements, which require innovative methods for forming strained semiconductor materials to enhance carrier mobility.
Innovation Solution
A method involving the formation of partially relaxed semiconductor materials, epitaxial growth of strained semiconductor materials in fin trenches, and subsequent removal of the remaining material to create fin structures with alternating strained silicon and germanium materials, enabling increased carrier mobility through compressive and tensile strains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional planar FET scaling is continued, then device performance improvement is achieved, but fundamental scaling limits are reached
Solution Approach 1:
The patent transitions from planar 2D FET geometry to 3D finFET structure with vertical channels, moving the current flow path into the third dimension. This dimensional change allows continued scaling without hitting the fundamental limits of planar geometry, enabling improved device performance while maintaining smaller effective channel dimensions.
2Reliability
If strained semiconductor materials are formed to enhance carrier mobility, then carrier mobility is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the fin structures into different material compositions - alternating layers of strained silicon and strained germanium - to provide different strain types (tensile and compressive) for optimizing both n-type and p-type carrier mobility. This segmentation allows targeted mobility enhancement in different regions while using established epitaxial growth processes.
Solution Approach 2:
The patent employs composite semiconductor structures combining multiple strained materials (silicon and germanium) with different lattice constants. By forming alternating layers of these materials in the fin structures, the patent creates composite channels that simultaneously provide tensile strain for electron mobility and compressive strain for hole mobility, enhancing overall device performance without requiring entirely new manufacturing approaches.
3Reliability
If alternating strained silicon and germanium materials are used in fin structures, then both hole and electron carrier mobility are enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent controls the epitaxial growth process by adjusting parameters such as temperature, pressure, and gas flow rates to achieve precise compositional control of alternating silicon and germanium layers. By optimizing these growth parameters, the patent maintains tight control over layer thickness and composition, ensuring consistent strain induction while managing the precision requirements of the manufacturing process.
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 enhances hole and electron carrier mobility in finFETs, facilitating continued performance improvements in semiconductor devices by leveraging the strain-induced performance enhancements in both p-type and n-type FinFETs.
Implementation Method 1
A first strained semiconductor material may then be epitaxially formed in a first portion of fin trenches, and a second strained semiconductor material may be epitaxially formed in a second portion of the fin trenches
Data Source
AI summary
A method of forming a semiconductor device that includes forming an at least partially relaxed semiconductor material, and forming a plurality of fin trenches in the partially relaxed semiconductor material. At least a portion of the plurality of fin trenches is filled with a first strained semiconductor material that is formed using epitaxial deposition. A remaining portion of the at least partially relaxed semiconductor material is removed to provide a plurality of fin structure of the first strained semiconductor material.