RP-CVD and Sputtering for Hydrogen-Free p-Type Layer Growth
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Solution Overview
Problem
Conventional III-nitride light emitting diodes (LEDs) face efficiency issues due to hydrogen-magnesium complex formation during MOCVD growth, which deactivates the p-type dopant, and the subsequent anneal process is hindered by the burial of the p-type layer under n-type layers, limiting the activation of p-type regions and reducing device efficiency.
Innovation Solution
Employing remote plasma chemical vapor deposition (RP-CVD) and sputtering deposition to grow layers without hydrogen or ammonia, allowing for a hydrogen-free ambient and preventing hydrogen incorporation into p-type regions, thereby eliminating the need for post-growth activation and enabling efficient growth of p-type layers and tunnel junctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MOCVD with ammonia is used to grow p-type layers, then the growth process is straightforward and commonly used, but hydrogen-magnesium complex forms which deactivates the p-type dopant and reduces device efficiency
Solution Approach 1:
The patent extracts and removes hydrogen from the growth environment by using RP-CVD with nitrogen plasma instead of ammonia-based MOCVD. This eliminates the source of hydrogen that forms deactivating complexes with magnesium dopant, thereby maintaining p-type dopant activation while enabling straightforward growth of p-type layers.
Solution Approach 2:
The patent changes the fundamental parameters of the growth process by switching from thermal MOCVD to plasma-enhanced RP-CVD. This parameter change modifies the chemical environment from hydrogen-containing ammonia decomposition to hydrogen-free nitrogen plasma, preventing hydrogen-magnesium complex formation while maintaining effective p-type doping.
2Reliability
If anneal process is used to break hydrogen-magnesium complex, then p-type activation can be restored, but the process is hindered by burial of p-type layer under n-type layers limiting activation effectiveness
Solution Approach 1:
The patent applies preliminary action by preventing hydrogen incorporation into the p-type layer during the growth process itself. By using hydrogen-free RP-CVD from the beginning, the hydrogen-magnesium complex never forms, eliminating the need for subsequent annealing processes to break the complexes and activate the dopant.
Solution Approach 2:
The patent converts the potential harm of complex post-growth processing into benefit by eliminating the anneal step entirely. The straightforward RP-CVD growth process directly produces activated p-type layers without requiring additional annealing equipment or process steps, simplifying the overall manufacturing complexity.
3Reliability
If RP-CVD and sputtering deposition are used to grow layers, then hydrogen-free ambient prevents hydrogen incorporation and maintains p-type activation, but the growth process becomes more complex
Solution Approach 1:
The patent applies universality by using RP-CVD as a multi-functional process that simultaneously achieves hydrogen-free growth environment, effective p-type doping, and high-quality layer formation. The same RP-CVD process can grow both n-type and p-type layers with appropriate dopant introduction, eliminating the need for separate MOCVD and specialized deposition equipment.
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 enhances the radiative efficiency of III-nitride LEDs by maintaining p-type layer activation, overcoming the limitations of conventional MOCVD methods, and enabling the creation of high-efficiency tunnel junction LEDs with improved current handling and optical flux per unit area.
Implementation Method 1
growing a light emitting device structure on a growth substrate... growing a tunnel junction on the light emitting device structure using at least one of RP-CVD and sputtering deposition
Implementation Method 2
remote plasma chemical vapor deposition (RP-CVD) and sputtering deposition to grow layers
Implementation Method 3
remote plasma chemical vapor deposition (RP-CVD) and sputtering deposition to grow layers
Data Source
AI summary
Described herein are methods for using remote plasma chemical vapor deposition (RP-CVD) and sputtering deposition to grow layers for light emitting devices. A method includes growing a light emitting device structure on a growth substrate, and growing a tunnel junction on the light emitting device structure using at least one of RP-CVD and sputtering deposition. The tunnel junction includes a p++ layer in direct contact with a p-type region, where the p++ layer is grown by using at least one of RP-CVD and sputtering deposition. Another method for growing a device includes growing a p-type region over a growth substrate using at least one of RP-CVD and sputtering deposition, and growing further layers over the p-type region. Another method for growing a device includes growing a light emitting region and an n-type region using at least one of RP-CVD and sputtering deposition over a p-type region.