GaN Ohmic Contact Electrode Surface Topography Control
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Solution Overview
Problem
Conventional methods for manufacturing ohmic contact electrodes in GaN-based devices result in low-quality electrodes with rough metal surfaces and uneven edges, leading to potential electric breakdown and reduced reliability and lifespan.
Innovation Solution
A method involving the growth of dielectric layers, ion implantation of silicon and indium ions, high-temperature annealing, and selective removal of these layers to form a smooth metal contact electrode, eliminating the need for high-temperature annealing of the metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fast thermal annealing process is performed on a metal layer at temperatures higher than 800°C to manufacture an ohmic contact electrode, then the manufacturing process can be completed, but the resulting electrode has rough metal surface topography and uneven metal edges
Solution Approach 1:
The patent applies preliminary action by forming a heavily doped N-type region in the semiconductor layer before depositing the metal layer. This pre-prepared highly conductive region serves as an ideal contact interface, eliminating the need for subsequent high-temperature annealing of the metal layer and thereby preventing surface roughening while maintaining effective ohmic contact formation.
Solution Approach 2:
The patent replaces the thermal annealing process (thermal system) with an ion implantation process (mechanical/system substitution). By implanting ions to create a heavily doped region, the method achieves the desired electrical contact properties without subjecting the metal layer to high-temperature thermal processing, thus avoiding surface degradation.
2Ease of manufacture
If a fast thermal annealing process is performed on a metal layer at temperatures higher than 800°C to manufacture an ohmic contact electrode, then the manufacturing process can be completed, but the resulting electrode has uneven metal edges which may cause electric breakdown
Solution Approach 1:
The patent applies preliminary action by forming a heavily doped N-type region in the semiconductor layer before depositing the metal layer. This pre-prepared highly conductive region ensures uniform electrical contact properties, eliminating the need for subsequent high-temperature annealing that causes edge irregularities and potential breakdown points, thereby improving device reliability.
Solution Approach 2:
The patent replaces the thermal annealing process (thermal system) with an ion implantation process (mechanical/system substitution). By implanting ions to create a heavily doped region, the method achieves uniform electrical contact properties without subjecting the metal layer to high-temperature thermal processing, thus preventing edge irregularities and improving device reliability.
3Ease of manufacture
If a fast thermal annealing process is performed on a metal layer at temperatures higher than 800°C to manufacture an ohmic contact electrode, then the manufacturing process can be completed, but the quality of the ohmic contact electrode is low
Solution Approach 1:
The patent applies preliminary action by forming a heavily doped N-type region in the semiconductor layer before depositing the metal layer. This pre-prepared highly conductive region serves as an ideal contact interface, eliminating the need for subsequent high-temperature annealing of the metal layer and thereby maintaining smooth surface topography and sharp edges, which significantly improves electrode quality.
Solution Approach 2:
The patent replaces the thermal annealing process (thermal system) with an ion implantation process (mechanical/system substitution). By implanting ions to create a heavily doped region, the method achieves the desired electrical contact properties without subjecting the metal layer to high-temperature thermal processing, thus preserving surface quality and improving overall electrode quality.
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 enables the production of high-quality ohmic contact electrodes with smooth surfaces and edges, ensuring stable breakdown voltage, improved reliability, and extended device lifespan.
Implementation Method 1
step S2: silicon ions and/or indium ions are implanted into a region of the first dielectric layer corresponding to an ohmic contact electrode region of the device and into the ohmic contact electrode region
Implementation Method 2
step S4: the silicon ions and/or the indium ions are activated using a high temperature annealing process, so as to form an N-type highly doped region
Data Source
AI summary
A method for preparing an ohmic contact electrode of a GaN-based device. Said method comprises the following steps: growing a first dielectric layer (203) on an upper surface of a device (S1); implanting silicon ions and/or indium ions in a region of the first dielectric layer (203) corresponding to an ohmic contact electrode region, and in the ohmic contact electrode region of the device (S2); growing a second dielectric layer (206) on an upper surface of the first dielectric layer (203) (S3); activating the silicon ions and/or the indium ions by means of a high temperature annealing process, so as to form an N-type heavy doping (S4); respectively removing portions, corresponding to the ohmic contact electrode region, of the first dielectric layer (203) and the second dielectric layer (206) (S5); growing a metal layer (208) on the upper surface of the ohmic contact electrode region of the device, so as to form an ohmic contact electrode (S6). The ohmic contact electrode prepared by the method can ensure that the metal layer (208) has flat surfaces, smooth and regular edges, and said electrode has stable device breakdown voltage, and is reliable and has a long service life.