Schottky Diode Lateral Epitaxial Overgrowth for Leakage Reduction
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Solution Overview
Problem
Conventional ESD protection circuits for RF systems face challenges in achieving high current density and low reverse leakage current, particularly with Schottky diodes which are needed for GaN RF frontend integration, as they often exhibit higher leakage current.
Innovation Solution
The fabrication of Schottky diodes using lateral epitaxial overgrowth with a highly doped and low defect density semiconductor layer formed during single operation regrowth, where a hard mask isolates the material from substrate defects, enabling high current density and low reverse bias leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional Schottky diodes are used for ESD protection, then current handling capacity is improved, but reverse leakage current increases
Solution Approach 1:
The patent applies local quality by creating a laterally-oriented component structure with highly doped semiconductor material specifically in the regions where Schottky barriers are formed. This localized high doping concentration optimizes the electrical properties at the metal-semiconductor interface, enabling high current density and low reverse leakage current specifically at the diode regions while maintaining other device functions elsewhere in the structure.
Solution Approach 2:
The patent transitions from conventional vertical diode structures to laterally-oriented diode components. The laterally-oriented anode and cathode regions extend in the lateral direction rather than vertically, creating a new dimensional configuration that reduces reverse leakage current paths while maintaining current handling capacity through extended lateral contact areas.
2Reliability
If lateral epitaxial overgrowth is used, then manufacturing complexity increases, but diode performance improves
Solution Approach 1:
The patent merges the formation of the highly doped semiconductor layer with the lateral epitaxial overgrowth process. The same epitaxial regrowth operation that creates the lateral structures also simultaneously forms the highly doped regions through in-situ doping, combining multiple fabrication steps into a single integrated process that reduces overall manufacturing complexity despite the advanced structures created.
Solution Approach 2:
The patent performs preliminary doping during the epitaxial growth process itself, before subsequent fabrication steps. The highly doped semiconductor material is incorporated during the lateral overgrowth phase, preparing the material properties in advance for optimal Schottky barrier formation and diode performance, eliminating the need for separate heavy doping steps.
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 results in Schottky diodes with high current handling capacity and minimal reverse leakage current, effectively addressing the current density and leakage challenges in ESD protection circuits.
Implementation Method 1
vertically oriented components of a first material adjacent sides of the hard mask and laterally oriented components of the first material on top of the hard mask
Data Source
AI summary
A diode is disclosed. The diode includes a semiconductor substrate, a hard mask formed above the substrate, vertically oriented components of a first material adjacent sides of the hard mask, and laterally oriented components of the first material on top of the hard mask. The laterally oriented components are oriented in a first direction and a second direction. The diode also includes a second material on top of the first material. The second material forms a Schottky barrier.