Nitride Semiconductor Buffer Layer Fe Concentration Profile
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Solution Overview
Problem
Existing nitride semiconductor substrates for high-electron mobility transistors (HEMTs) face challenges in achieving optimal characteristics such as low leakage current and high electron mobility due to the difficulty in managing iron (Fe) concentration profiles, which often result in reduced performance and increased risk of crack formation.
Innovation Solution
A nitride semiconductor substrate with a buffer layer doped with Fe, where the Fe concentration increases monotonically from the substrate interface, reaches a maximum value within a specific range, and then decreases towards the active layer interface, positioned away from both interfaces to maintain high resistance and flatness, thereby reducing leakage current and enhancing electron mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer intermediate structure is introduced to capture Fe, then Fe penetration into the channel layer is suppressed, but the device structure becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the Fe concentration parameter within the buffer layer rather than introducing additional structural elements. By controlling the Fe concentration to decrease from the lower to upper portion of the buffer layer, the patent achieves Fe penetration suppression through a continuous concentration gradient. This approach avoids the need for discrete multilayer intermediate structures, thereby reducing device complexity while maintaining the desired Fe capture function.
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 coexistence of multiple desirable characteristics in a simple structure, effectively reducing leakage current and enabling high-speed operation while maintaining high resistance, thus improving the overall performance of HEMTs.
Implementation Method 1
The buffer layer contains Fe, and the Fe has a concentration profile, in which the Fe concentration increases monotonically and gradually in the thickness direction of the buffer layer
Data Source
AI summary
The characteristic of Fe-doped HEMTs is improved. The invention provides a nitride semiconductor substrate having a substrate, a buffer layer made of nitride semiconductors on the substrate, and an active layer composed of nitride semiconductor layers on the buffer layer; the buffer layer containing Fe, the Fe having a concentration profile in which the Fe concentration increases monotonically and gradually in the thickness direction of the buffer layer from an interface between the substrate and the buffer layer, has a maximum value within 2×1017 to 1.1×1020 atoms/cm3 inclusive, and decreases monotonically and gradually toward an interface between the buffer layer and the active layer, and the point of the maximum value being within ±50 nm from the midpoint in the thickness direction of the buffer layer, and being 500 nm or more away from the interface between the buffer layer and the active layer.