Sidewall Schottky Interface Recess Design for Leakage Reduction
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Solution Overview
Problem
Known Schottky devices are prone to manufacturing defects and have undesirable performance characteristics, such as variability in leakage and forward voltage drop, due to misalignment and doping issues during fabrication.
Innovation Solution
A Schottky device design featuring dual sidewall Schottky interfaces formed by doped regions and a metal layer along the sidewalls of a recess, with a bottom surface excluding a Schottky interface, which enhances robustness against manufacturing variability and improves pinch-off performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional Schottky device structure is used, then the device can be manufactured with standard processes, but the device exhibits high variability in leakage and forward voltage drop due to misalignment and doping issues
Solution Approach 1:
The patent transitions from a planar Schottky interface to a three-dimensional sidewall Schottky interface formed along the vertical walls of a trench. This dimensional change allows the Schottky interface to be formed on the sidewalls of the trench rather than on a horizontal surface, making the device performance less sensitive to lateral misalignment and doping variations during manufacturing.
Solution Approach 2:
The Schottky interface is segmented into multiple discrete contact points along the trench sidewalls rather than forming a continuous planar interface. This segmentation is achieved by creating a trench structure where the Schottky metal contacts the semiconductor along the vertical walls at multiple locations, reducing the impact of local defects and variability on overall device performance.
2Ease of manufacture
If the Schottky interface is formed on the bottom surface of the recess, then the manufacturing process is simplified, but the device exhibits undesirable leakage characteristics
Solution Approach 1:
The patent extracts the Schottky interface formation from the bottom surface of the trench and relocates it exclusively to the sidewalls. By removing the Schottky interface from the bottom surface, the design eliminates the leakage pathway that would exist through the bottom contact, while maintaining the necessary electrical connection through the sidewall contacts.
3Productivity
If standard doping processes are used during fabrication, then the manufacturing process remains simple, but the device exhibits variability in forward voltage drop and leakage due to doping issues
Solution Approach 1:
The patent applies local quality by creating distinct doping regions along the trench sidewalls where the Schottky interface forms. The doping concentration and profile are optimized locally at the sidewall contact regions to ensure consistent Schottky barrier formation, while other regions of the semiconductor structure maintain different doping characteristics appropriate for their specific functions.
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
The dual sidewall Schottky interface design provides consistent performance and reduced leakage, even with manufacturing variability, and achieves a relatively low forward voltage drop, making the device more reliable and efficient.
Implementation Method 1
The first doped region and the metal layer collectively define a Schottky interface with the sidewall of the recess. The second doped region and the metal layer collectively define a Schottky interface with the sidewall of the recess.
Data Source
AI summary
In one general aspect, a device can include a first trench disposed in a semiconductor region, a second trench disposed in the semiconductor region, and a recess disposed in the semiconductor region between the first trench and the second trench. The recess has a sidewall and a bottom surface. The device also includes a Schottky interface along a sidewall of the recess and the bottom surface of the recess excludes a Schottky interface.