Nitride Semiconductor Low-Resistance Layer Fabrication
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Solution Overview
Problem
Existing methods for forming low-resistance layers in nitride semiconductor devices face challenges such as increased production costs and reliability issues due to high-temperature annealing requirements and unstable etching processes, which can lead to short-circuiting and signal loss.
Innovation Solution
A method involving the formation of ohmic electrodes on a nitride semiconductor layer, followed by annealing to create a low-resistance layer, and then removing the electrodes to form source and drain electrodes with asymmetrical spacing relative to the gate electrode, reducing electrical resistance and preventing short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature annealing is used to form a low-resistance layer, then electrical resistance is reduced, but production cost increases and manufacturing complexity increases
Solution Approach 1:
The patent changes the temperature parameter of the annealing process from high temperature (conventional) to low temperature (invention), achieving the formation of a low-resistance layer without requiring high-temperature equipment, thereby reducing production cost and manufacturing complexity while maintaining the electrical resistance reduction effect
Solution Approach 2:
The patent uses a sacrificial electrode structure that is removed after forming the low-resistance layer, creating a template or copy approach where the electrode pattern guides the low-resistance layer formation, then the electrode is discarded, avoiding the need for complex direct patterning processes
2Manufacturing precision
If etching is used to form the low-resistance layer, then electrode spacing is controlled, but manufacturing reliability decreases due to unstable etching processes
Solution Approach 1:
The patent replaces the chemical etching process with a physical removal process using lift-off technique, where a sacrificial electrode is removed by lifting it off from the substrate, avoiding the instability of chemical etching processes while maintaining precise electrode spacing control
Solution Approach 2:
The patent introduces a sacrificial electrode as an intermediary element that temporarily exists to define the low-resistance layer region, then is removed, serving as a mediator between the desired electrode spacing and the final device structure, eliminating the need for unstable etching processes
3Ease of manufacture
If symmetric electrode spacing is used, then manufacturing is simplified, but short-circuiting risk increases between gate electrode and source/drain electrodes
Solution Approach 1:
The patent employs asymmetric spacing between the gate electrode and source/drain electrodes, where the distance is intentionally made unequal, creating different safety margins for short-circuit prevention while maintaining manufacturing simplicity through the lift-off process that naturally defines the asymmetric geometry
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 reduces electrical resistance and signal loss while maintaining reliability and reducing manufacturing costs by avoiding high-temperature annealing and unstable etching processes.
Implementation Method 1
forming a low-resistance layer between an uppermost surface of the nitride semiconductor layer and the ohmic electrodes by annealing the nitride semiconductor layer
Data Source
AI summary
A method for fabricating a semiconductor device includes forming ohmic electrodes on a source region and a drain region of a nitride semiconductor layer, forming a low-resistance layer between an uppermost surface of the nitride semiconductor layer and the ohmic electrodes by annealing the nitride semiconductor layer, removing the ohmic electrodes from at least one of the source region and the drain region after forming the low-resistance layer, and forming at least one of a source electrode and a drain electrode on the low-resistance layer, the at least one of a source electrode and a drain electrode having an edge, a distance between the edge and a gate electrode is longer than a distance between an edge of the low-resistance layer and the gate electrode.