Ga2O3 Semiconductor Device Nitrogen Doping Leakage Current
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Solution Overview
Problem
Ga2O3-based crystal films grown without doping often become n-type unintentionally, leading to leakage currents in semiconductor devices like FETs, requiring additional acceptor impurities to compensate and enhance resistance.
Innovation Solution
A Ga2O3-based semiconductor device with a nitrogen-doped region in the Ga2O3-based crystal layer, where the nitrogen concentration can be higher or lower than the unintentionally doped donor concentration, acting as a current path or channel region in various device configurations such as Schottky barrier diodes, MOSFETs, and MESFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an undoped Ga2O3-based crystal film is used as a buffer layer, then the device structure is simple, but leakage current flows through the buffer layer causing the FET to fail normal operation
Solution Approach 1:
The patent applies local quality by creating a buffer layer with non-uniform nitrogen concentration. The nitrogen concentration is higher near the substrate interface and decreases toward the channel layer, forming a gradient structure. This localized variation in doping concentration allows the buffer layer to simultaneously provide high resistance at the interface (reducing leakage) while maintaining appropriate electrical characteristics in the upper regions for proper FET operation.
2Reliability
If an acceptor impurity is added to compensate unintentional donors, then resistance is increased, but the device structure becomes more complex
Solution Approach 1:
The patent merges the buffer layer formation and acceptor doping into a single integrated process. Nitrogen is introduced during the epitaxial growth of the buffer layer itself, combining the functions of buffer layer creation and resistance enhancement. This eliminates the need for separate doping steps and simplifies the overall device structure while achieving the desired high resistance to prevent leakage current.
3Reliability
If nitrogen is doped at high concentration to compensate donors, then resistance is enhanced, but electron concentration increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the nitrogen concentration profile and using nitrogen atoms that act as acceptors rather than donors. By changing the dopant type from group IV elements (which can be unintentional donors) to nitrogen (which acts as an acceptor in Ga2O3), the patent achieves resistance enhancement through hole compensation without increasing electron concentration, thereby maintaining proper electrical characteristics.
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
The nitrogen-doped region effectively compensates unintentional donors, reducing electron concentration and enhancing resistance, allowing for proper operation of semiconductor devices by acting as an acceptor impurity, thereby improving device performance.
Implementation Method 1
N (nitrogen) acts as an acceptor impurity in a Ga2O3-based crystal
Data Source
AI summary
A Ga2O3-based semiconductor device includes a Ga2O3-based crystal layer including a donor, and an N-doped region formed in at least a part of the Ga2O3-based crystal layer.