Nitride Semiconductor Films via Pulsed Sputtering at Low Temperature
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Solution Overview
Problem
Conventional methods for growing group 13 nitride semiconductors, such as MOCVD, face challenges in achieving high-quality films with low impurity concentrations and high electron mobility, especially at high donor concentrations, due to thermodynamic restrictions and incorporation of carbon and hydrogen impurities.
Innovation Solution
The pulsed sputtering deposition (PSD) method is used to form nitride semiconductor films at low temperatures, allowing for the growth of high-quality films with low resistivity and high electron mobility by controlling parameters like growth rate, substrate temperature, and oxygen incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the MOCVD method is used to grow nitride semiconductor films, then high-quality films with low impurity concentrations can be achieved, but the process temperature must exceed 1000°C which increases manufacturing complexity
Solution Approach 1:
The patent changes the fundamental growth mechanism from chemical vapor deposition (MOCVD) to physical vapor deposition (pulsed sputtering), transforming the process from chemistry-driven to physics-driven. This parameter change enables low-temperature growth while maintaining film quality, as the sputtering process uses physical ejection of atoms rather than chemical reactions requiring high temperatures
Solution Approach 2:
The patent replaces the thermal/chemical field (MOCVD) with a mechanical/physical field (sputtering). The sputtering process uses ion bombardment and physical ejection to deposit material, substituting the thermal decomposition and chemical reactions of MOCVD with a mechanically-driven physical vapor deposition process
2Temperature
If the MBE method is used to form compound semiconductor films at low temperature, then the manufacturing cost increases and the area size of the film is limited
Solution Approach 1:
The patent makes the sputtering process universally applicable to large-area substrates by using a planar magnetron configuration that can cover extensive areas. The method can simultaneously deposit uniform films over large surfaces, making it suitable for mass production while maintaining low-temperature processing capabilities
Solution Approach 2:
The patent uses an inert gas atmosphere (argon or nitrogen) during sputtering to prevent oxidation and contamination, creating a controlled environment that enables low-temperature growth without the need for ultra-high vacuum systems required by MBE, thereby reducing manufacturing complexity and cost
3Quantity of substance
If donors are incorporated at high concentration using the MBE method, then the transparency of the compound semiconductor film decreases due to absorption by high concentration donor level
Solution Approach 1:
The patent changes the doping mechanism from thermal diffusion and chemical incorporation (MBE) to physical implantation and co-deposition via sputtering. This allows precise control of donor concentration and distribution, enabling high doping levels without the same degree of optical absorption because the dopants are incorporated more uniformly and with less clustering
4Productivity
If the growth rate is increased to improve productivity, then the film quality and electron mobility deteriorate
Solution Approach 1:
The patent uses pulsed sputtering where the deposition occurs in periodic pulses rather than continuous deposition. Each pulse allows for controlled atom arrival and incorporation, and the periodic nature enables thermal relaxation and uniform distribution between pulses, maintaining high film quality even at high average growth rates
Solution Approach 2:
The patent employs dynamic control of sputtering parameters including pulse duration, duty cycle, and ion bombardment energy. By dynamically adjusting these parameters during deposition, the process can accommodate high growth rates while maintaining the conditions necessary for high electron mobility and film quality
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 films with low resistivity and high electron mobility, even at high electron concentrations, facilitating the manufacture of high-performance electronic and light-emitting devices without the need for buffer layers and with reduced manufacturing costs.
Implementation Method 1
a pulsed-sputtering a target metal containing at least Ga in a chamber in a process atmosphere containing noble gas, nitrogen gas and oxygen to form a film of the compound semiconductor
Data Source
AI summary
A nitride compound semiconductor having a low resistivity that is conventionally difficult to be manufactured is provided. Since the nitride compound semiconductor exhibits a high electron mobility, a high-performance semiconductor device may be configured. The present invention may provide, at a high productivity, a group 13 nitride semiconductor of an n-type conductivity that may be formed as a film on a substrate having a large area size and has a mobility of 70 to 140 cm2/(V·s) by a pulsed sputtering method performed in a process atmosphere at room temperature to 700° C.