GaN Test Structures for Small-Pitch Defect Detection
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Solution Overview
Problem
Existing GaN-based high-voltage devices face inefficiencies in detecting defects, particularly those smaller than the widely spaced components, leading to compromised performance due to defects in semiconductor layers and mismatch issues with non-GaN substrates.
Innovation Solution
Incorporation of test structures with alternately arranged or metal-insulator-metal (MIM) configurations that emulate GaN-based device components, allowing for concurrent formation with a smaller pitch to detect defects accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional defect detection techniques are used on GaN-based devices, then the detection process is simple, but defects smaller than the component pitch cannot be detected
Solution Approach 1:
The patent creates simplified test structures that copy the essential features of GaN-based device components (transistors, capacitors, interconnects) at a reduced pitch scale. These test structures replicate the manufacturing process and material layers of actual devices, allowing defects to be detected in a controlled test environment before full device fabrication. The test structures serve as scaled-down models that maintain the same defect susceptibility as production devices.
Solution Approach 2:
The patent divides the defect detection function into separate test structures that are distinct from the main GaN-based devices. These test structures are fabricated independently in dedicated test regions, allowing defect detection to be performed without affecting production device functionality. The segmentation enables parallel processing where test structures can be evaluated separately from functional devices.
2Ease of manufacture
If GaN-based devices are fabricated on non-GaN substrates, then manufacturing is easier, but lattice mismatch defects occur
Solution Approach 1:
The patent modifies the test structure design to accommodate non-GaN substrates by adjusting layer thicknesses, material compositions, and structural parameters. The test structures incorporate buffer layers and transition layers with graded compositions that gradually adapt from the non-GaN substrate to the GaN active layers, reducing lattice mismatch stress and dislocation formation while maintaining compatibility with standard manufacturing processes.
3Measurement precision
If test structures with smaller pitch are used to detect smaller defects, then defect detection accuracy improves, but manufacturing complexity increases
Solution Approach 1:
The patent creates simplified test structures that copy the essential features of GaN-based device components (transistors, capacitors, interconnects) at a reduced pitch scale. These test structures replicate the manufacturing process and material layers of actual devices, allowing defects to be detected in a controlled test environment before full device fabrication. The test structures serve as scaled-down models that maintain the same defect susceptibility as production devices.
Data Source
AI summary
A semiconductor device includes a transistor comprising: a plurality of layers, wherein each of the plurality of layers has at least one Group III-V compound material; a gate electrode operatively coupled to at least one of the plurality of layers; a source electrode disposed on a first side of the gate electrode; a drain electrode disposed on a second side of the gate electrode; a field plate disposed between the gate electrode and the drain electrode; and a plurality of conductive lines disposed above the gate electrode, the source electrode, and the drain electrode. The semiconductor device further includes a plurality of test structures, wherein each of the test structures, including a first metal pattern and a second metal pattern, emulates at least one of the gate electrode, the source electrode, the drain electrode, the field plate, or at least one of the plurality of conductive lines.