GaN HEMT Gate Stack for Higher Breakdown and Lower Leakage
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Solution Overview
Problem
Conventional GaN-based High Electron Mobility Transistors (HEMTs) face issues with relatively low breakdown voltage, particularly in enhancement mode devices, which complicates circuit structures and affects safety.
Innovation Solution
A semiconductor structure with a specific configuration including a P-type semiconductor layer, an aluminum-containing film layer, and a gate contact layer, aligned sidewalls, and N-type doped source and drain regions, along with a heterojunction design to enhance breakdown voltage and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P-type gate is adopted in a conventional GaN-based HEMT device to achieve enhancement mode, then the device can operate in enhancement mode, but the breakdown voltage remains relatively low
Solution Approach 1:
The patent employs a composite gate structure consisting of multiple layers including P-type semiconductor layer, aluminum-containing film layer, and gate contact layer. This composite structure combines the advantages of different materials to achieve both enhancement mode operation and high breakdown voltage, resolving the contradiction between reliability improvement and device complexity
Solution Approach 2:
The patent introduces a vertical multi-layer stacking dimension to the gate structure, transitioning from a conventional single-layer P-type gate to a multi-layer composite gate. This dimensional change allows for optimized electrical properties at each layer interface, achieving high breakdown voltage while maintaining enhancement mode operation
2Ease of manufacture
If a conventional P-type gate structure is used, then the device structure is relatively simple, but the breakdown voltage is relatively low and circuit safety is reduced
Solution Approach 1:
The gate structure is segmented into multiple functional layers, each with specific thickness and material composition. This segmentation allows independent optimization of each layer's properties to maximize breakdown voltage while maintaining manufacturability through standard semiconductor fabrication processes
3Reliability
If the aluminum-containing film layer thickness is increased, then the breakdown voltage is improved, but the gate leakage current may increase
Solution Approach 1:
The patent optimizes the thickness parameter of the aluminum-containing film layer to a specific range that balances breakdown voltage enhancement and leakage current suppression. By precisely controlling this parameter within an optimal window, both contradictory requirements are satisfied
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 structure increases breakdown voltage and reduces gate leakage current, simplifying fabrication and improving the reliability and performance of GaN-based HEMT devices.
Implementation Method 1
the aluminum-containing film layer is located between the gate contact layer and the first P-type semiconductor layer... the aluminum-containing film layer reduces a gate leakage current of the semiconductor device by blocking an electron tunneling
Data Source
AI summary
Disclosed are a semiconductor structure and a fabricating method thereof. The semiconductor structure includes a substrate, a channel layer, a barrier layer and a first P-type semiconductor layer stacked sequentially, the channel layer and the barrier layer form a heterojunction, and the 2DEG at the channel may be depleted by the first P-type semiconductor layer, so as to implement an enhancement mode device; and a sidewall of the first P-type semiconductor layer, a sidewall of the aluminum-containing film layer, and a sidewall of the gate contact layer that are aligned are stacked sequentially on the barrier layer in a gate region, and a material of the aluminum-containing film layer includes at least any one of AlN, AlON or Al2O3.