Nickel Oxide Heterojunction Diode Carrier Control by Oxygen Sputtering
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Solution Overview
Problem
The challenge of implementing a pn homojunction-based β-Ga2O3 device is due to the large effective hole mass of p-type dopants and high acceptor activation energy in gallium oxide, making it difficult to achieve high-performance power semiconductor devices.
Innovation Solution
A method of controlling carrier concentration in nickel oxide layers by adjusting the oxygen flow ratio during sputtering in mixed gas atmospheres of argon and oxygen, forming p-type nickel oxide blocks with varying carrier concentrations to create a nickel oxide-gallium oxide heterojunction diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p-type dopants are used in gallium oxide to create pn homojunction, then device functionality is achieved, but high acceptor activation energy and large effective hole mass make it difficult to achieve high performance
Solution Approach 1:
The patent changes the material parameter by switching from p-type doped gallium oxide to nickel oxide with inherently different electrical properties. By adjusting the oxygen flow ratio during sputtering, the carrier concentration in nickel oxide is controlled to create p-type characteristics, eliminating the need for traditional p-type dopants in gallium oxide and their associated high activation energy problems.
Solution Approach 2:
The patent creates a heterojunction structure combining n-type gallium oxide and p-type nickel oxide. This composite material approach leverages the advantages of both materials: gallium oxide provides high breakdown field and low cost, while nickel oxide provides efficient p-type conduction, together achieving high-performance power devices without the limitations of pn homojunction.
2Quantity of substance
If oxygen flow ratio is increased during sputtering, then carrier concentration in nickel oxide is adjusted, but deposition rate and layer properties change
Solution Approach 1:
The patent employs dynamic adjustment of the oxygen flow ratio during the sputtering process to control carrier concentration in the nickel oxide layer. By varying the oxygen content in the sputtering atmosphere, the electrical properties of the deposited layer are tuned in real-time, allowing optimization of both carrier concentration and deposition characteristics for different device requirements.
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 allows for the formation of a nickel oxide-gallium oxide heterojunction diode with improved breakdown voltage, leakage current, and turn-on voltage characteristics, enhancing the performance of power semiconductor devices.
Implementation Method 1
depositing a first p nickel oxide layer on the n-type gallium oxide epitaxial layer by sputtering a nickel oxide target, in a first mixed gas atmosphere of argon and oxygen, and sputtering the nickel oxide target in a second mixed gas atmosphere of argon and oxygen to deposit a second p nickel oxide layer
Data Source
AI summary
A method for controlling the carrier concentration of nickel oxide is disclosed. The method for controlling the carrier concentration of nickel oxide comprises the steps of: preparing an n-type gallium oxide substrate on which an n-type gallium oxide epitaxial layer is formed; sputtering a nickel oxide target in a first mixed gas atmosphere of argon and oxygen, thereby depositing a first p-type nickel oxide layer on the n-type gallium oxide epitaxial layer, and sputtering the nickel oxide target in a second mixed gas atmosphere of argon and oxygen, thereby depositing a second p-type nickel oxide layer on the n-type gallium oxide epitaxial layer.