Polar Rare-Earth Oxide 2DEG Structure for Low-Leakage III-N Gates
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Solution Overview
Problem
Conventional non-polar rare-earth oxide layers have limited dielectric permittivity, restricting the thickness of these layers and leading to increased current leakage, which hinders the efficient growth of electronic devices, particularly those with two-dimensional electron gas (2DEG) over III-N layers with non-polar orientation.
Innovation Solution
The development of layered structures incorporating polar-oriented rare-earth oxide layers, which enhance dielectric permittivity, allowing for the growth of thicker field-effect transistor (FET) gate layers and reducing leakage current, by diffusing electrons to form an n-type 2DEG on III-N layers, and optionally including rare-earth silicide or epitaxial metal layers for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-polar rare-earth oxide layers are used, then the device structure is simple, but the dielectric permittivity is limited and current leakage increases
Solution Approach 1:
The patent employs a composite layered structure consisting of polar rare-earth oxide layer, non-polar rare-earth oxide layer, and III-N layer. This composite structure combines the high dielectric permittivity of polar REO with the structural stability of non-polar REO, achieving both low leakage current and reliable device operation without using complex alternative materials
Solution Approach 2:
The invention applies different orientations of rare-earth oxide layers at different locations within the structure. The polar REO layer is positioned adjacent to the III-N layer to maximize dielectric permittivity and reduce leakage, while the non-polar REO layer provides structural support. This local differentiation of material properties optimizes performance while maintaining overall structural simplicity
2Productivity
If non-polar rare-earth oxide layers are used, then the manufacturing process is simple, but the layer thickness is limited and device efficiency decreases
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the rare-earth oxide layer from non-polar to polar configuration. This parameter change increases the dielectric permittivity from approximately 12-14 to greater than 20, enabling thicker gate layers and improved device efficiency while maintaining compatibility with existing manufacturing processes for growing oxide layers
3Reliability
If polar rare-earth oxide layers are used, then the dielectric permittivity increases and leakage current decreases, but the manufacturing process becomes more complex
Solution Approach 1:
The non-polar rare-earth oxide layer serves as an intermediary between the polar REO layer and the underlying substrate or other layers. This intermediary layer facilitates the growth of the polar REO layer with high dielectric permittivity while managing interface quality and reducing defects, thereby enabling the manufacturing benefits of polar REO without the full complexity of growing thick polar oxide layers directly
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 increased dielectric permittivity of polar-oriented rare-earth oxide layers enables the growth of more efficient electronic devices with reduced leakage current, facilitating the integration of 2DEG and photonic devices on non-polar or semi-polar III-N substrates, enhancing device efficiency and performance.
Implementation Method 1
the polar rare earth oxide layer has at least a first portion of electrons that diffuse to an interface between the polar rare-earth oxide layer and the III-N layer or are transferred to the III-N layer to form an n-type 2-dimensional electron gas (2DEG) on the III-N layer
Data Source
AI summary
Layered structures described herein include electronic devices with 2-dimensional electron gas between polar-oriented cubic rare-earth oxide layers on a non-polar semiconductor. Layered structure includes a semiconductor device, comprising a III-N layer or rare-earth layer, a polar rare-earth oxide layer grown over the III-N layer or rare-earth layer, a gate terminal deposited or grown over the polar rare-earth oxide layer, a source terminal that is deposited or epitaxially grown over the layer, and a drain terminal that is deposited or grown over the layer.