Group III Nitride Growth Using Hydrogen-Free Nitrogen Plasma
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Solution Overview
Problem
Conventional methods for producing group III nitride semiconductors at low temperatures result in increased carbon content, leading to decreased bulk mobility and film quality due to the formation of methane-based compounds during the plasma process.
Innovation Solution
A method and apparatus that utilize a plasma generator to create nitrogen radicals without hydrogen, allowing for the formation of group III nitride semiconductors at temperatures between 800°C and 1000°C, using organometallic gases like trimethylgallium, while controlling the pressure and nitrogen radical density to suppress carbon incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the temperature is reduced to form group III nitride semiconductor film by plasma method, then substrate cracking is prevented, but carbon content in the film increases
Solution Approach 1:
The patent changes the chemical composition parameters of the plasma gas from conventional ammonia-based or hydrogen-containing mixtures to a hydrogen-free nitrogen-based plasma. This parameter change allows the process to proceed at lower temperatures (800-1000°C) without generating methane-based compounds, thereby simultaneously preventing substrate cracking and maintaining low carbon content in the film.
Solution Approach 2:
The patent creates an inert hydrogen-free plasma environment by using nitrogen gas as the plasma source. This inert environment prevents hydrogen from reacting with the organometallic gas to form methane, thereby eliminating the source of carbon contamination while still enabling low-temperature film formation that avoids substrate thermal stress and cracking.
2Quantity of substance
If ammonia gas is thermally decomposed at high temperature, then nitrogen source is provided for film growth, but substrate is stressed by heat causing film cracks
Solution Approach 1:
The patent replaces the thermal decomposition mechanism (mechanical/thermal system) with a plasma-based chemical activation mechanism. Instead of relying on high temperature to decompose ammonia and provide nitrogen, the patent uses plasma excitation to generate reactive nitrogen species at lower temperatures, thereby eliminating thermal stress on the substrate while maintaining adequate nitrogen supply for film growth.
Solution Approach 2:
The patent changes the temperature parameter from high temperature (1100°C or higher required for ammonia decomposition) to low temperature (800-1000°C) by introducing plasma as an alternative activation mechanism. This parameter change allows nitrogen supply without subjecting the substrate to excessive thermal stress that causes film cracking.
3Use of energy by moving object
If hydrogen-containing gas is used in plasma process, then plasma generation is facilitated, but methane-based compounds are formed increasing carbon content
Solution Approach 1:
The patent creates a hydrogen-free inert plasma environment by using nitrogen gas as the plasma source. This eliminates hydrogen from the system, preventing the formation of methane-based compounds that would increase carbon content in the film, while still maintaining effective plasma generation for low-temperature film formation.
Solution Approach 2:
The patent extracts and removes hydrogen from the plasma gas composition, using only nitrogen-based gases. This extraction of the harmful hydrogen component eliminates the source of methane formation and carbon contamination, while the nitrogen plasma continues to provide the necessary activation for film growth at low temperatures.
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 reduces carbon content in the semiconductor films, enhancing their bulk mobility and quality by preventing the formation of methane-based compounds and allowing for low-temperature deposition without substrate cracking.
Implementation Method 1
supplying a first gas that contains a nitrogen gas without containing a hydrogen gas to a plasma generator and turning the first gas into plasma by the plasma generator
Implementation Method 2
an excitation gas supply step of supplying an excitation gas to the substrate inside the chamber, the excitation gas being obtained by supplying a first gas that contains a nitrogen gas without containing a hydrogen gas to a plasma generator and turning the first gas into plasma by the plasma generator
Implementation Method 3
a heating step of heating the substrate by a heater provided inside the chamber
Implementation Method 4
a decompression step of reducing a pressure inside the chamber by a suction part
Implementation Method 5
an organometallic gas (for example, trimethylgallium) as a gallium source and an ammonia (NH3) gas as a nitrogen source are supplied to the substrate, and a gallium nitride film is grown on the substrate with gallium and nitrogen generated by thermal decomposition
Implementation Method 6
a group III nitride semiconductor film can be formed on a substrate at a relatively low temperature
Data Source
AI summary
A method for producing a group III nitride semiconductor includes a loading step (S1), a decompression step (S2), a heating step (S3), an excitation gas supply step (S5), and an organometallic gas supply step (S6). In the loading step (Si), a substrate is loaded into a chamber. In the decompression step (S2), a suction part reduces a pressure inside the chamber. In the heating step (S3), a heater provided inside the chamber heats the substrate. In the excitation gas supply step (S5), a first gas that contains nitrogen without containing hydrogen is supplied to a plasma generator, and an excitation gas obtained by turning the first gas into plasma by the plasma generator is supplied to the substrate inside the chamber. In the organometallic gas supply step (S6), a second gas that is an organometallic gas that contains a group III element is supplied to the substrate inside the chamber.