Nitride Semiconductor Through-Hole Metallization Without Stopper Regions
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Solution Overview
Problem
Existing semiconductor devices face challenges in downsizing due to the inability of metal layers to make Ohmic contact with semiconductor layers, leading to increased complexity and size from the need for separate regions for etching stoppers.
Innovation Solution
A semiconductor device configuration with a substrate, first nitride semiconductor layer, first metal layer, second metal layer with higher etching resistance, and a fourth metal layer on the inner surface of through-holes, allowing the second metal layer to function as an etching stopper without a separate region, enabling downsizing by eliminating the need for additional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate region for etching stopper is provided, then etching resistance is improved, but device size increases
Solution Approach 1:
The patent merges the etching stopper function with the metal layer structure by forming the metal layer to extend into the through-hole and expose the second metal layer at the bottom. This integration eliminates the need for a separate etching stopper region, achieving both high etching resistance and compact device size.
Solution Approach 2:
The metal layer structure performs multiple functions simultaneously: it provides electrical connection, acts as an etching stopper, and enables Ohmic contact with the semiconductor layer. The second metal layer specifically serves as both a conductive layer and an etching stopper, eliminating the need for dedicated stopper regions.
2Reliability
If metal layer makes Ohmic contact with semiconductor layer, then electrical conductivity is improved, but device complexity increases
Solution Approach 1:
The patent combines the Ohmic contact function with the metal layer structure by directly forming the metal layer on the semiconductor layer. The first metal layer makes Ohmic contact with the nitride semiconductor layer, eliminating the need for separate contact structures and reducing overall device complexity.
Solution Approach 2:
The patent uses a composite metal layer structure with multiple materials (first metal layer, second metal layer) where each layer has specific properties. The first metal layer provides Ohmic contact capability while the second metal layer provides etching resistance, creating a composite structure that achieves multiple functions simultaneously.
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 configuration allows for the downsizing of semiconductor devices by utilizing the second metal layer as an etching stopper, reducing the device's size while maintaining effective etching and Ohmic contact capabilities.
Implementation Method 1
the first metal layer makes an Ohmic contact with the first nitride semiconductor layer
Implementation Method 2
Resistance of the second metal layer to etching using a reactive gas is higher than resistance of the first metal layer to etching using the reactive gas
Data Source
AI summary
A semiconductor device includes a substrate, a first nitride semiconductor layer, a first metal layer, a b second metal layer, a third metal layer, and a fourth metal layer. The substrate, first nitride semiconductor layer, and first metal layer have a through-hole that penetrates the substrate, first nitride semiconductor layer, and first metal layer and to which the second metal layer is exposed. The first metal layer makes an Ohmic contact with the first nitride semiconductor layer. Resistance of the second metal layer to etching using a reactive gas is higher than resistance of the first metal layer to etching using the reactive gas. Resistivity of the third metal layer is lower than resistivity of the first metal layer and resistivity of the second metal layer. The fourth metal layer is on an inner surface of the through-hole and is in direct contact with the second metal layer.