Ga2O3 Crystal Film Si Concentration Control via SiO2 Cell
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Solution Overview
Problem
The challenge in growing Ga2O3-based crystal films using MBE is the difficulty in controlling the vapor pressure of Si sources, leading to inaccurate dopant concentration and potential segregation of Sn dopants, which affects the uniformity of the dopant distribution.
Innovation Solution
A method involving the production of Si-containing vapors by heating Si or Si compounds in contact with Ga, using an MBE apparatus with a SiO2 cell, allows for precise control of Si concentration in the Ga2O3-based crystal film, enhancing dopant uniformity, and includes a crystal multilayer structure with undoped and Si-doped (AlGa)2O3 layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Si is used as a dopant for Ga2O3-based crystal film, then the carrier concentration can be controlled, but it is difficult to control the vapor pressure of vaporized Si source to achieve accurate Si concentration control
Solution Approach 1:
The patent introduces a SiO2 cell as an intermediary component between the Si source and the Ga2O3 substrate. The SiO2 cell serves as a mediator that releases Si atoms during MBE growth, enabling precise control of Si concentration in the crystal film without directly controlling the vapor pressure of Si source. This intermediary approach simplifies the doping process while maintaining accurate dopant concentration control.
2Measurement precision
If Sn is used as a dopant to control carrier concentration with high accuracy, then the carrier concentration can be precisely controlled, but Sn is difficult to introduce into the film at the initial growth stage and is likely to segregate on the growth surface
Solution Approach 1:
The patent employs Si as a disposable dopant source that is introduced through the SiO2 cell during the initial growth stage. Si atoms are readily incorporated into the Ga2O3 crystal lattice from the beginning of growth, avoiding the segregation issues experienced with Sn. The Si dopant is consumed during the growth process, providing stable and uniform dopant distribution throughout the crystal film.
3Manufacturing precision
If Sn is used as the dopant, then the carrier concentration can be controlled with high accuracy, but Sn is likely to segregate on the growth surface affecting uniformity
Solution Approach 1:
The patent changes the dopant element from Sn to Si, which fundamentally alters the doping behavior. Si has different physical and chemical properties that enable it to be uniformly incorporated into the Ga2O3 crystal lattice during MBE growth. This parameter change (dopant element selection) resolves the segregation issue while maintaining accurate dopant concentration control through the SiO2 cell mechanism.
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 method enables highly accurate control of dopant concentration and uniformity in Ga2O3-based crystal films, specifically achieving a Si concentration range of 3.0×10^17/cm^3 to 3.5×10^19/cm^3, and forms a crystal multilayer structure suitable for high electron mobility transistors.
Implementation Method 1
it is difficult to control the vapor pressure of vaporized Si source such as Si, SiO and SiO2 to control the Si concentration of the Ga2O3-based crystal film
Implementation Method 2
the Si-containing vapor is produced by heating Si or a Si compound and Ga while allowing the Si or the Si compound to contact with the Ga
Implementation Method 3
A method of growing a conductive Ga2O3-based crystal film by MBE, comprising producing a Ga vapor and a Si-containing vapor and supplying the vapors as molecular beams onto a surface of a Ga2O3-based crystal substrate so as to grow the Ga2O3-based crystal film
Data Source
AI summary
A method of growing a conductive Ga2O3-based crystal film by MBE includes producing a Ga vapor and a Si-containing vapor and supplying the vapors as molecular beams onto a surface of a Ga2O3-based crystal substrate so as to grow the Ga2O3-based crystal film. The Ga2O3-based crystal film includes a Si-containing Ga2O3-based single crystal film. The Si-containing vapor is produced by heating Si or a Si compound and Ga while allowing the Si or a Si compound to contact with the Ga.