GaN Substrate Buffer Layer to Block Aluminum Diffusion
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Solution Overview
Problem
Current semiconductor devices, particularly gallium nitride (GaN) devices, face challenges in achieving low on-resistance, high switching frequency, high breakdown voltage, and high-temperature operation while minimizing leakage current and electrical signal loss.
Innovation Solution
A semiconductor substrate with a base, insulating layer, semiconductor layer, wide bandgap diffusion buffer layer, and nucleation layer is developed, where the wide bandgap diffusion buffer layer has a bandgap higher than 2.5 eV and an aluminum-containing nucleation layer is used to prevent aluminum diffusion into the semiconductor layer, reducing leakage current and signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional semiconductor structure is used, then manufacturing is simpler, but leakage current increases and signal loss occurs due to aluminum diffusion
Solution Approach 1:
A wide bandgap diffusion buffer layer is introduced as an intermediary between the nucleation layer and the semiconductor layer. This buffer layer prevents aluminum atoms from diffusing into the semiconductor layer while maintaining device performance, thereby reducing leakage current and signal loss without requiring fundamental changes to the overall device architecture
Solution Approach 2:
The patent employs a composite layer structure combining materials with different bandgap energies. The wide bandgap diffusion buffer layer (with bandgap >2.5 eV) is composite with the nucleation layer and semiconductor layer, creating a multi-material stack that exploits the unique properties of each material to achieve both low leakage current and manufacturability
2Power
If high power operation is achieved, then device capability improves, but on-resistance and thermal management become critical challenges
Solution Approach 1:
The patent changes the bandgap parameter of the diffusion buffer layer to be greater than 2.5 eV, which is wider than conventional buffer layers. This parameter change reduces thermal excitation of carriers and minimizes leakage current at high temperatures, enabling reliable high-power operation with stable on-resistance characteristics
Solution Approach 2:
The wide bandgap diffusion buffer layer provides localized quality improvement at the critical interface between the nucleation layer and semiconductor layer. By concentrating the wide bandgap property where aluminum diffusion is most problematic, the device achieves low on-resistance and good thermal stability without requiring the entire structure to be optimized
3Speed
If switching frequency is increased, then device performance improves, but electrical signal loss and leakage current increase
Solution Approach 1:
The wide bandgap diffusion buffer layer acts as an intermediary that blocks aluminum diffusion pathways, thereby reducing leakage current and electrical signal loss. This enables the device to operate at high switching frequencies without suffering from excessive energy loss, as the buffer layer maintains signal integrity through the critical interface region
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 solution effectively reduces leakage current and electrical signal loss in semiconductor devices, enabling them to operate efficiently with low on-resistance and high switching frequency, even at high temperatures.
Implementation Method 1
a wide bandgap diffusion buffer layer... wherein the bandgap of the wide bandgap buffer diffusion layer is higher than 2.5 eV... to prevent aluminum diffusion into the semiconductor layer
Data Source
AI summary
Provided are a semiconductor substrate and a transistor. The semiconductor substrate includes a base, an insulating layer, a semiconductor layer, a wide bandgap diffusion buffer layer and a nucleation layer. The insulating layer is disposed on the base. The semiconductor layer is disposed on the insulating layer. The wide bandgap diffusion buffer layer is disposed on the semiconductor layer, wherein the bandgap of the wide bandgap buffer diffusion layer is higher than 2.5 eV. The nucleation layer is disposed on the wide bandgap diffusion buffer layer, wherein the nucleation layer includes an aluminum-containing layer.