Reverse Polarization Layer in AlInN HEMTs
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Solution Overview
Problem
AlInN-based high electron mobility transistors (HEMTs) suffer from inferior electron mobility and breakdown voltage due to alloy scattering, interface roughness, and high gate leakage current, stemming from the large dissociation temperature difference between AlN and InN, which complicates the preparation of high-quality AlInN layers and degrades device performance.
Innovation Solution
Incorporating a reverse polarization layer with a specific thickness ratio between 0.5 and 3 times the thickness of an AlxIn1-xN layer, made of materials like GaN or InGaN with lower Al composition, to balance positive charges and reduce the polarization field, thereby enhancing electron mobility and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Al composition in AlInN layer is increased to enhance spontaneous polarization and 2DEG, then 2DEG concentration increases, but alloy scattering and interface roughness increase causing electron mobility to decrease
Solution Approach 1:
The AlInN layer is segmented into high-Al and low-Al composition regions. The high-Al segment (0.6-0.8) provides strong spontaneous polarization to generate high 2DEG concentration, while the low-Al segment (0.1-0.3) reduces alloy scattering and interface roughness to maintain high electron mobility. This segmentation resolves the contradiction between increasing 2DEG concentration and maintaining electron mobility.
2Stability of the object's composition
If AlInN layer is used instead of AlGaN, then lattice matching with GaN is improved eliminating cracks, but breakdown voltage and electron mobility remain inferior due to material preparation difficulties
Solution Approach 1:
The AlInN structure is segmented into multiple layers with different Al compositions. The high-Al layer maintains lattice matching with GaN to prevent cracks, while the low-Al layer reduces alloy scattering and preparation difficulties. This segmentation enables AlInN to achieve both good lattice matching and high breakdown voltage, overcoming the limitations of conventional AlInN-based HEMTs.
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 implementation of a reverse polarization layer increases electron mobility, raises the conduction band, decreases leakage current, and significantly improves breakdown voltage, while reducing the dynamic on-state resistance ratio, effectively addressing the limitations of AlInN-based HEMTs.
Implementation Method 1
Incorporating a reverse polarization layer with a specific thickness ratio between 0.5 and 3 times the thickness of an AlxIn1-xN layer, made of materials like GaN or InGaN with lower Al composition, to balance positive charges and reduce the polarization field
Data Source
AI summary
In one aspect of the present disclosure, a semiconductor device includes a channel layer, an AlxIn1-xN layer on the channel layer with a thickness of t1, and a reverse polarization layer on the AlxIn1-xN layer with a thickness of t2. The thickness is 0.5×t1≤t2≤3×t1. In another aspect of the present disclosure, a method of manufacturing a semiconductor device is provided. The method including: forming a channel layer on a substrate; forming an AlxIn1-xN layer on the channel layer with a thickness of t1; and forming a reverse polarization layer on the AlxIn1-xN layer with a thickness of t2. The thickness is 0.5×t1≤t2≤3×t1.