Nitride Semiconductor Laminate with Protective Layer
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Solution Overview
Problem
The challenge in manufacturing nitride semiconductor laminates, free-standing substrates, and semiconductor devices lies in achieving high purity due to contamination issues when growing semiconductor layers on nitrogen-polar surfaces at high temperatures, which leads to thermal decomposition and impurity contamination from the substrate reverse surface.
Innovation Solution
A nitride semiconductor laminate is fabricated using a substrate with a nitrogen-polar surface and a group III element-polar reverse surface, where a protective layer with higher heat resistance is applied to the reverse surface to suppress thermal decomposition and impurity contamination, allowing for the growth of a semiconductor layer with low oxygen and carbon concentrations at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a semiconductor layer is grown on a nitrogen-polar surface at high temperature, then crystal quality can be improved, but thermal decomposition occurs and impurities contaminate the semiconductor layer
Solution Approach 1:
A protective layer is introduced as an intermediary between the substrate and the semiconductor layer. This protective layer has higher heat resistance than the substrate and prevents direct contact between the high-temperature growth environment and the substrate reverse surface, thereby preventing thermal decomposition and impurity contamination while allowing high-quality crystal growth to proceed
2Manufacturing precision
If growth temperature is increased to improve crystal quality, then manufacturing precision improves, but thermal decomposition and impurity contamination worsen
Solution Approach 1:
The protective layer serves as a thermal barrier that decouples the growth temperature from the substrate temperature. This allows the semiconductor layer to be grown at high temperatures for improved crystal quality while the protective layer prevents the substrate from reaching decomposition temperatures
Solution Approach 2:
The invention changes the thermal properties of the substrate system by adding a protective layer with higher heat resistance. This parameter change allows the system to withstand higher growth temperatures without substrate decomposition, thereby improving crystal quality without the harmful effects of thermal decomposition
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 approach enables the production of nitride semiconductor laminates and devices with high purity, reducing impurity concentrations and maintaining smooth surface morphology, even at growth temperatures above 1250°C, thereby enhancing crystal quality and insulating properties.
Implementation Method 1
thermal decomposition and impurity contamination from the substrate reverse surface
Implementation Method 2
a semiconductor layer including a group III nitride semiconductor may be epitaxially grown on a predetermined substrate by vapor phase epitaxy
Implementation Method 3
a semiconductor layer including a group III nitride semiconductor may be epitaxially grown on a predetermined substrate by vapor phase epitaxy
Data Source
AI summary
A nitride semiconductor laminate includes: a substrate comprising a group III nitride semiconductor and including a surface and a reverse surface, the surface being formed from a nitrogen-polar surface, the reverse surface being formed from a group III element-polar surface and being provided on the reverse side from the surface; a protective layer provided at least on the reverse surface side of the substrate and having higher heat resistance than the reverse surface of the substrate; and a semiconductor layer provided on the surface side of the substrate and comprising a group III nitride semiconductor. The concentration of O in the semiconductor layer is lower than 1×1017 at/cm3.