Fe-Doped GaN Semiconductor Buffer Layer for Fe Entrapment
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Solution Overview
Problem
Doping GaN-based semiconductor layers with Fe can lead to surface precipitation and entrapment of Fe during growth, resulting in degraded device characteristics due to trapped carriers and impurity scattering, which contradicts the intended improvement in device performance.
Innovation Solution
Incorporating a first buffer layer of AlN or AlxGa1-xN (0.4<x<1) between the Fe-doped GaN semiconductor layer and the operating layer to suppress Fe entrapment by confining precipitated Fe at interfaces, thereby reducing Fe concentration in the operating layer and maintaining device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Fe is doped into GaN-based semiconductor layer to improve device characteristics, then leakage current is suppressed and pinch-off characteristic is improved, but Fe precipitates on surface and entraps in operating layer causing degradation of device characteristics
Solution Approach 1:
A first buffer layer made of AlN or AlxGa1-xN (0.4<x<1) is introduced between the Fe-doped GaN semiconductor layer and the operating layer. This intermediary buffer layer suppresses Fe entrapment in the operating layer while allowing the semiconductor layer to maintain high resistance through Fe doping. The buffer layer acts as a mediator that prevents harmful Fe precipitation from reaching the operating layer.
Solution Approach 2:
The structure is divided into multiple layers: a semiconductor layer with Fe doping for high resistance, a first buffer layer for suppressing Fe entrapment, and an operating layer for device operation. This segmentation allows each layer to perform its specific function - the semiconductor layer provides resistance control through Fe doping while the buffer layer prevents Fe contamination of the operating layer.
2Reliability
If Fe doping concentration is increased to improve device characteristics, then leakage current suppression is enhanced, but Fe precipitation and entrapment increase causing mobility degradation
Solution Approach 1:
The first buffer layer serves as an intermediary that decouples the Fe doping concentration in the semiconductor layer from the Fe concentration in the operating layer. This allows high Fe doping concentrations to be used in the semiconductor layer for effective leakage current suppression without proportionally increasing Fe entrapment in the operating layer, as the buffer layer intercepts and confines Fe precipitation.
3Reliability
If Fe is doped to improve pinch-off characteristic, then device performance is enhanced, but impurity scattering increases reducing electron mobility
Solution Approach 1:
The first buffer layer acts as a mediator that allows Fe doping in the semiconductor layer to improve pinch-off characteristics while preventing Fe-induced impurity scattering in the operating layer. By confining Fe precipitation at the interface between the semiconductor layer and buffer layer, the buffer layer protects the operating layer from Fe-related scattering mechanisms.
Data Source
AI summary
A semiconductor device includes: a semiconductor layer made of Fe-doped GaN; a first buffer layer that is provided on the semiconductor layer so as to contact an upper surface of the semiconductor layer and is made of AlN or AlxGa1-xN (0.4<x<1); and an operating layer that is provided on the first buffer layer and is made of a GaN-based semiconductor.