Monovalent Organogallium ALD for GaN Crystallinity
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Solution Overview
Problem
Current methods for forming high crystalline gallium nitride (GaN) thin films using atomic layer deposition (ALD) face challenges with precursor instability, high-temperature requirements, and contamination from carbon and inorganic impurities, particularly when using trimethylgallium (TMG) and triethylgallium (TEG), which are difficult to handle and result in poor crystallization.
Innovation Solution
The method involves feeding a monovalent organogallium complex, such as a cyclopentadienyl complex, into a reaction chamber at a substrate temperature of 350° C or less, followed by a nitriding gas, preferably nitrogen plasma, with an optional oxygen-free reducing gas to eliminate impurities, and using a thin gallium oxide pretreatment to enhance crystallinity without high-temperature thermal treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If trimethylgallium (TMG) or triethylgallium (TEG) are used as precursors in ALD, then GaN films can be formed, but the precursors are unstable in air and ignite spontaneously, making them difficult to handle
Solution Approach 1:
The patent changes the chemical parameters of the gallium precursor from conventional TMG/TEG to a stable organometallic complex that does not ignite spontaneously. This parameter change in chemical stability allows the precursor to be handled safely in air while still forming high-quality GaN films through ALD process
Solution Approach 2:
The patent uses a stable organometallic complex precursor that can be stored and handled without special precautions, replacing the need for expensive and complex handling systems required for unstable precursors like TMG and TEG
2Stability of the object's composition
If high temperature thermal treatment or annealing techniques are used to form high crystalline GaN thin film, then crystallinity is improved, but the process complexity and energy consumption increase
Solution Approach 1:
The patent performs preliminary action by using a specifically designed stable organometallic complex precursor that enables direct formation of high crystalline GaN films without requiring subsequent high-temperature annealing or laser treatment. The precursor is pre-engineered to produce the desired crystalline structure upon deposition
Solution Approach 2:
The patent extracts and eliminates the high-temperature thermal treatment and annealing steps from the conventional ALD process. By using the stable organometallic complex precursor, the method achieves high crystallinity through the deposition process alone, removing the need for additional complex thermal processing steps
3Quantity of substance
If conventional precursors are used in ALD, then GaN films can be deposited, but carbon and inorganic impurities contaminate the film, reducing quality
Solution Approach 1:
The patent changes the chemical composition parameters of the gallium precursor to a stable organometallic complex that contains no carbon or inorganic impurities. This parameter change in precursor chemistry ensures high-purity GaN film deposition while maintaining efficient deposition rates through the ALD process
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 high crystalline GaN films with minimal impurities and improved crystallinity on various substrates, including silicon, without the need for high-temperature annealing or laser treatment, resulting in films with low carbon and oxygen content and a N/Ga ratio close to unity.
Implementation Method 1
feeding a nitriding gas, preferably nitrogen plasma
Implementation Method 2
forming a crystalline gallium nitride thin film by an atomic layer deposition (ALD) method
Implementation Method 3
feeding a monovalent organogallium complex into a reaction chamber where a substrate temperature is 350° C. or less
Implementation Method 4
using a thin gallium oxide pretreatment to enhance crystallinity
Data Source
AI summary
Provided is a more efficient method of manufacturing a GaN film by the atomic layer deposition (ALD), wherein a high crystalline GaN film containing very few impurities is manufactured using a monovalent gallium compound without high-temperature thermal treatment such as laser annealing. The method of manufacturing a crystalline gallium nitride thin film by the ALD comprises a step 1 of feeding a monovalent organogallium complex into a reaction chamber where a substrate temperature is 350° C. or less, and a step 2 of feeding a nitriding gas into the reaction chamber.