Asymmetric Via Contact Structure for Scaled MOSFET Reliability
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Solution Overview
Problem
The scale-down of metal-oxide-semiconductor field-effect transistors (MOSFETs) in semiconductor devices leads to deterioration in operational properties, necessitating improvements in electrical and reliability characteristics.
Innovation Solution
The semiconductor device incorporates a via contact design with inclined side surfaces at obtuse and acute angles to connect active contacts to power lines, allowing for efficient electrical connections while maintaining reliability, and a method of fabrication that includes selective epitaxial growth and etching processes to form semiconductor patterns and contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If MOSFETs are scaled down to meet increasing demand for smaller pattern size, then device size is reduced, but operational properties deteriorate
Solution Approach 1:
The patent transitions from two-dimensional planar contacts to three-dimensional inclined via contacts. The via contacts are formed with asymmetric inclination angles (first angle and second angle) relative to the top surface of the active contact, creating a tilted structure that extends in the vertical dimension. This dimensional change allows improved electrical connection without increasing the lateral footprint, thus maintaining small device size while enhancing operational properties through better contact geometry and reduced resistance.
2Reliability
If active contact length is extended to improve electrical connection, then electrical characteristics improve, but fabrication complexity increases
Solution Approach 1:
The patent employs asymmetric inclination angles for the via contact side surfaces. The first side surface is inclined at a first angle to the top surface of the active contact, while the second side surface is inclined at a second angle, where the first angle is an obtuse angle and the second angle is an acute angle. This asymmetric geometry improves electrical connection efficiency by optimizing the contact area and current distribution, while the structured asymmetric design actually simplifies fabrication by enabling selective etching processes that can naturally form these angles without requiring complex multi-step alignment procedures.
Data Source
AI summary
A semiconductor device may include: a first source/drain pattern; a first active contact on the first source/drain pattern; a power line above the first active contact; and a first via contact connecting the first active contact to the power line, wherein the first via contact comprises a first side surface and a second side surface, which are opposite to each other in a first direction, the first side surface is inclined at a first angle to a top surface of the first active contact, the second side surface is inclined at a second angle to the top surface of the first active contact, and the first angle is an obtuse angle, and the second angle is an acute angle.