AlGaN/GaN HEMT High-Resistance Al-Si-N Layer Current Density
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Solution Overview
Problem
High-current operation in nitride semiconductor devices leads to current concentration at electrode ends, risking breakdown due to high current density, which existing techniques fail to adequately address.
Innovation Solution
Incorporating a high-resistance layer with a higher electric resistance value than the electrodes in at least one electrode of the compound semiconductor device, specifically in the form of Al—Si—N layers, to alleviate current density concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ion implantation or increasing Al composition ratio is used to enable higher-current operation, then operating current is improved, but current density concentration at electrode ends increases causing breakdown risk
Solution Approach 1:
The patent applies local quality by creating a high-resistance layer specifically at the lower portion of the electrode where current density concentration occurs. This localized modification allows the electrode to have different resistance characteristics in different regions: high resistance at the base to prevent current concentration, and low resistance at the contact area to maintain good electrical connection. This resolves the contradiction by addressing the reliability issue locally without compromising the overall current-carrying capability.
Solution Approach 2:
The patent changes the electrical resistance parameter of the electrode structure by introducing a high-resistance layer with controlled resistivity. This parameter change allows the electrode to redistribute current density, preventing excessive concentration at the electrode ends while maintaining sufficient current flow. The high-resistance layer acts as a current-spreading structure that mitigates the breakdown risk associated with high current density.
2Reliability
If a high-resistance layer is added to reduce current density concentration, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies the nesting principle by integrating the high-resistance layer within the existing electrode structure. The high-resistance layer is positioned at the lower portion of the electrode, effectively nested inside the electrode assembly. This approach adds the necessary functional layer without requiring separate external components or complex interconnections, thereby improving reliability while minimizing increases in device complexity.
Solution Approach 2:
The patent employs composite materials by combining the electrode material with a high-resistance layer material to create a multi-layer electrode structure. This composite structure integrates the current-spreading function of the high-resistance layer with the electrical connection function of the electrode, achieving both reliability improvement and structural integration in a single component assembly.
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 high-resistance layer effectively reduces current density at the electrode ends, enhancing the reliability and high-withstand-voltage capability of AlGaN/GaN HEMTs for high-current operations.
Implementation Method 1
a high-resistance layer higher in an electric resistance value than the electrodes is formed in a lower portion of at least one electrode
Data Source
AI summary
An AlGaN/GaN HEMT includes: a compound semiconductor layer; a source electrode and a drain electrode formed on an upper side of the compound semiconductor layer; and an Al—Si—N layer being a high-resistance layer disposed in a lower portion of at least one of the source electrode and the drain electrode and higher in an electric resistance value than the source electrode and the drain electrode.