Beta-Ga2O3 Semiconductor Element Buffer Layer Impurity Diffusion
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Solution Overview
Problem
In MESFETs, the acceptor impurity from the high-resistivity Ga2O3 substrate diffuses into the channel layer, increasing its resistance due to carrier compensation, which is not effectively addressed by existing technologies.
Innovation Solution
A semiconductor element and crystalline laminate structure are designed with a β-Ga2O3-based substrate, buffer layer, and channel layer, where the buffer layer and channel layer have specific impurity concentrations and orientations to prevent acceptor impurity diffusion, using a β-Ga2O3-based single crystal with a donor impurity and acceptor impurity, and a buffer layer structure that suppresses acceptor impurity diffusion from the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-resistivity Ga2O3 substrate containing acceptor impurity is used, then the substrate provides high resistivity and structural support, but the acceptor impurity diffuses into the channel layer causing resistance increase due to carrier compensation
Solution Approach 1:
An undoped buffer layer is introduced as an intermediary between the high-resistivity substrate containing acceptor impurity and the donor impurity-containing channel layer. This buffer layer acts as a diffusion barrier that prevents acceptor impurity from migrating into the channel layer, thereby maintaining channel layer purity and preventing resistance increase while allowing the substrate to provide its structural support and stability functions
Solution Approach 2:
The structure is segmented into three distinct layers: the high-resistivity substrate, an undoped buffer layer, and a donor impurity-containing channel layer. This segmentation separates the functions of each layer, allowing the substrate to provide high resistivity and mechanical support while the buffer layer prevents impurity diffusion and the channel layer maintains high conductivity through donor impurity doping
2Device complexity
If the channel layer is directly formed on the high-resistivity substrate, then the device structure is simplified, but acceptor impurity diffusion into the channel layer increases resistance
Solution Approach 1:
The undoped buffer layer serves as a mediator between the substrate and channel layer, preventing direct contact that would allow acceptor impurity diffusion. This intermediary layer maintains channel layer conductivity by blocking the diffusion path of acceptor impurity from the substrate, while adding only one additional layer to the device structure
3Manufacturing precision
If donor impurity concentration in the channel layer is increased to maintain conductivity, then channel layer resistance is reduced, but acceptor impurity diffusion from substrate becomes more significant due to carrier compensation
Solution Approach 1:
The undoped buffer layer acts as a protective intermediary that blocks acceptor impurity diffusion from the substrate to the channel layer. This allows the channel layer to maintain optimal donor impurity concentration for high conductivity without suffering from carrier compensation effects, as the buffer layer prevents acceptor impurity from reaching the channel layer to cause compensation
Solution Approach 2:
Different regions of the device have different doping characteristics: the substrate has high acceptor impurity concentration for high resistivity, the buffer layer is undoped to act as a diffusion barrier, and the channel layer has controlled donor impurity concentration for high conductivity. This local quality differentiation allows each layer to perform its specific function optimally
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 design effectively prevents the increase in resistance of the channel layer by controlling impurity concentrations and orientations, ensuring high conductivity and suppressing carrier compensation, thereby enhancing the performance of the semiconductor element.
Implementation Method 1
the acceptor impurity may be diffused from the high-resistivity Ga2O3 substrate into the channel layer such that the resistance of the channel layer increases due to carrier compensation
Data Source
AI summary
A semiconductor element includes a high-resistivity substrate that includes a β-Ga2O3-based single crystal including an acceptor impurity, a buffer layer on the high-resistivity substrate, the buffer layer including a β-Ga2O3-based single crystal, and a channel layer on the buffer layer, the channel layer including a β-Ga2O3-based single crystal including a donor impurity. A crystalline laminate structure includes a high-resistivity substrate that includes a β-Ga2O3-based single crystal including an acceptor impurity, a buffer layer on the high-resistivity substrate, the buffer layer including a β-Ga2O3-based single crystal, and a donor impurity-containing layer on the buffer layer, the donor impurity-containing layer including a β-Ga2O3-based single crystal including a donor impurity.