Nitride Semiconductor Device Hydrogen Trapping Insulating Film
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Solution Overview
Problem
Conventional nitride semiconductor devices have residual hydrogen in the p-type layer, leading to increased resistance and operating voltage, which affects the efficiency and reliability of semiconductor devices like laser diodes and LEDs, making it difficult to achieve high power and long life.
Innovation Solution
A nitride semiconductor device with a p-type layer and an insulating film containing hydrogen-trapping impurities, such as fluorine, is used to reduce residual hydrogen concentration by trapping it in the impurity region, thereby reducing the acceptor activation ratio and preventing increases in operating voltage and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a p-type layer is grown by MOCVD method, then the layer can be formed with acceptor dopants, but residual hydrogen remains at high concentration causing increased resistance
Solution Approach 1:
An insulating film containing hydrogen-trapping impurities (such as fluorine, boron, or aluminum) is introduced as an intermediary layer between the p-type layer and the upper structure. This intermediary film captures and traps residual hydrogen atoms, preventing them from degrading the p-type layer's electrical properties. The impurities in the insulating film act as hydrogen sinks, effectively reducing hydrogen concentration in the p-type layer without requiring additional processing steps on the p-type layer itself.
2Reliability
If annealing process is performed to activate p-type layer, then acceptor activation is improved, but hydrogen remains trapped reducing effectiveness
Solution Approach 1:
The insulating film containing hydrogen-trapping impurities is formed before the p-type layer activation process. This preliminary action ensures that when annealing is performed to activate the acceptors in the p-type layer, any hydrogen released during heating is immediately trapped by the impurities in the insulating film. This prevents hydrogen from re-trapping at acceptor sites and maintains high acceptor activation ratio throughout the activation process.
3Reliability
If residual hydrogen is reduced by conventional methods, then resistance decreases, but operating voltage and current increase due to electron overflow
Solution Approach 1:
The insulating film with hydrogen-trapping impurities serves as a mediator that continuously manages hydrogen concentration in the p-type layer. By maintaining low hydrogen levels throughout device operation and stacking processes, the p-type layer maintains low resistance and high hole concentration. This prevents electron overflow from the active layer into the p-type layer, thereby keeping operating voltage and current at acceptable levels despite the presence of multiple layers and processing steps.
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 effectively suppresses the increase in operating voltage and current, leading to higher power and longer life for nitride semiconductor devices by reducing hydrogen concentration in the p-type layer without generating crystal defects, thus enhancing device reliability and efficiency.
Implementation Method 1
an insulating film contacting the p-type semiconductor layer and having an impurity region containing second impurities for trapping hydrogen
Data Source
AI summary
A nitride semiconductor device includes: a semiconductor substrate; a p-type semiconductor layer formed over the semiconductor substrate, made of a nitride semiconductor, and containing first impurities; and an insulating film contacting the p-type semiconductor layer and having an impurity region containing second impurities for trapping hydrogen. Since residual hydrogen in the p-type semiconductor layer is trapped in the impurity region, the hydrogen concentration in the impurity region is higher than that in the insulating film excluding the impurity region.