Semiconductor Isolation Trench Liner Oxygen Diffusion
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Solution Overview
Problem
Current semiconductor device manufacturing techniques face challenges in minimizing the 'width effect' caused by oxygen diffusion from shallow trench isolation (STI) into high-k gate insulators, which degrades device performance, particularly in CMOS transistors, due to limitations in existing methods such as additional masking layers, process complexity, and variability.
Innovation Solution
A method involving the use of a trench liner material that inhibits the nucleation of high-k materials, allowing the high-k gate material to be divided by the liner, thereby preventing oxygen migration and reducing the width effect by creating a discontinuity between the STI and high-k gate insulator sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow trench isolation (STI) is used to separate transistors, then device isolation is improved, but oxygen diffusion from STI into high-k gate insulator causes width effect that degrades device performance
Solution Approach 1:
A liner layer is introduced as an intermediary barrier between the STI region and the high-k gate insulator. This liner prevents oxygen atoms from diffusing through the STI into the high-k material, thereby eliminating the width effect while maintaining proper device isolation. The liner acts as a diffusion barrier that mediates the interaction between STI and gate insulator.
Solution Approach 2:
The gate insulator structure is segmented into multiple sections by the liner layer, which creates discrete regions separated by the isolation trench. This segmentation prevents continuous oxygen diffusion paths and allows independent control of oxygen exposure in different gate regions, reducing the width effect.
2Object-affected harmful factors
If additional masking layers are added to reduce width effect, then oxygen diffusion is reduced, but process complexity increases
Solution Approach 1:
The liner layer formation is merged with the existing STI fabrication process flow. The liner is deposited as part of the isolation module along with the STI trench formation and filling, combining multiple functions into a single integrated process sequence rather than adding separate masking and deposition steps.
3Object-affected harmful factors
If oxygen scavenging metals are used to create metal gate layer, then oxygen diffusion is reduced, but control issues and process variability increase
Solution Approach 1:
The liner layer serves as a stable intermediary barrier that provides consistent oxygen diffusion blocking without the control issues associated with oxygen scavenging metals. The liner's thickness and material properties can be precisely controlled during deposition, providing predictable and repeatable performance across manufacturing batches.
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 effectively minimizes oxygen diffusion into the high-k gate insulator over active transistor regions, enhancing device performance by reducing the width effect and maintaining process control, while avoiding additional complexity and variability issues.
Implementation Method 1
a trench liner material that inhibits the nucleation of high-k materials
Implementation Method 2
preventing oxygen migration and reducing the width effect by creating a discontinuity between the STI and high-k gate insulator sections
Data Source
Figure 1A~1B
Figure 2
Figure 3~5
AI summary
A method of manufacturing a semiconductor device (300) is provided herein, where the width effect is reduced in the resulting semiconductor device (300). The method involves providing a substrate (200) having semiconductor material (202), forming an isolation trench (212) in the semiconductor material (202), and lining the isolation trench (212) with a liner material (214) that substantially inhibits formation of high-k material thereon. The lined trench (216) is then filled with an insulating material (218). Thereafter, a layer of high-k gate material (232) is formed over at least a portion of the insulating material (218) and over at least a portion of the semiconductor material (202). The liner material (214) divides the layer of high-k gate material (232), which prevents the migration of oxygen over the active region of the semiconductor material (202).