Semiconductor Contact Plug Strain Engineering for Carrier Mobility
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high reliability, performance, and multifunctionality due to limitations in carrier mobility and integration density, particularly in field effect transistors.
Innovation Solution
The semiconductor device incorporates an insulating layer with vertically spaced semiconductor patterns, a gate structure that encloses the channel region, and contact plugs made of conductive metal nitrides or metals that exert strain on the channel region, enhancing carrier mobility by applying tensile or compressive strain depending on the transistor type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact plugs are formed to extend through source/drain regions and into the insulating layer, then carrier mobility is improved through strain application, but device complexity increases due to additional structural elements and fabrication steps
Solution Approach 1:
The contact plug structure is segmented into multiple portions: a first portion extending through the source/drain region, a second portion extending into the insulating layer, and optionally a third portion at the interface. This segmentation allows different materials and strain characteristics to be applied in different regions, optimizing carrier mobility while managing structural complexity through functional division.
Solution Approach 2:
The contact plug employs composite material structure with different metal materials in different portions. The first portion uses a metal material optimized for electrical contact, while the second portion uses a metal material specifically selected to exert tensile strain on the channel region. This composite approach enables simultaneous optimization of electrical performance and strain-induced carrier mobility enhancement.
2Reliability
If metal materials are selected to exert strain on the channel region, then carrier mobility increases, but manufacturing precision requirements increase due to material selection and strain control
Solution Approach 1:
Different metal materials are applied to different portions of the contact plug based on local requirements. The first portion uses material optimized for electrical conductivity and contact properties, while the second portion uses material specifically selected for its strain-exerting capability on the channel region. This local quality differentiation enables precise strain control in the critical channel region while maintaining overall manufacturing feasibility.
Solution Approach 2:
The invention changes material parameters (metal composition, crystal structure, lattice constant) in different portions of the contact plug to achieve desired strain characteristics. By selecting metal materials with specific physical parameters, the strain magnitude and direction can be controlled to optimize carrier mobility in the channel region.
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 improves carrier mobility in both NMOSFET and PMOSFET transistors, increasing the device's performance and reliability by optimizing the strain distribution across the channel regions.
Implementation Method 1
The respective contact plugs include a metal material that exerts a strain on the channel region. For example, the metal material may be a conductive metal nitride or metal that exerts the strain on the channel region, such that the strain on the channel region is a tensile strain that is greater or more uniform than that provided by a semiconductor material of the source/drain regions.
Data Source
AI summary
A semiconductor device includes an insulating layer on a substrate, a channel region on the insulating layer, a gate structure on the insulating layer, the gate structure crossing the channel region, source/drain regions on the insulating layer, the source/drain regions being spaced apart from each other with the gate structure interposed therebetween, the channel region connecting the source/drain regions to each other, and contact plugs connected to the source/drain regions, respectively. The channel region includes a plurality of semiconductor patterns that are vertically spaced apart from each other on the insulating layer, the insulating layer includes first recess regions that are adjacent to the source/drain regions, respectively, and the contact plugs include lower portions provided into the first recess regions, respectively.