RF Sputtering Passivation for III-V Semiconductor Interfaces
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Solution Overview
Problem
The formation of interfacial states and Fermi-level pinning at the semiconductor-to-metal-oxide interface in III-V semiconductor-based MOSFETs reduces charge mobility, and existing passivation methods like thermal and plasma oxidation, and atomic layer deposition have limitations, such as high oxide bulk trap densities and excessive leakage current.
Innovation Solution
The use of RF sputtering to grow a dielectric layer on III-V semiconductors in an atmosphere containing inert gases and oxygen, which creates a self-cleaning process that preserves the semiconductor surface, resulting in a high mobility interface with charge mobility comparable to the bulk semiconductor, and allows for control of charge carrier density and mobility through sputtering power and oxygen concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal, anodic or plasma oxidation is used to form native oxides on GaAs surface, then passivation is achieved, but high oxide bulk trap densities and excessive leakage current occur
Solution Approach 1:
The patent changes the deposition method parameters by using atomic layer deposition (ALD) instead of thermal, anodic, or plasma oxidation. This parameter change results in the formation of Al2O3 with lower bulk trap densities and reduced leakage current, while maintaining effective passivation of the GaAs surface
Solution Approach 2:
The patent employs ALD process with controlled oxidant exposure that prevents excessive oxidation. The controlled oxidation environment in ALD avoids the formation of high-density trap states while still achieving effective surface passivation, unlike strong oxidation methods that create excessive leakage current
2Reliability
If ALD is used to deposit Al2O3 on GaAs, then interface self-cleaning effect occurs eliminating native GaAs surface oxides, but process complexity and cost increase
Solution Approach 1:
The patent utilizes the self-cleaning effect inherent in the ALD process where the first few ALD cycles automatically remove native GaAs surface oxides without requiring separate cleaning steps. The ALD process itself performs the cleaning function, making the system self-service and eliminating additional process complexity
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 achieves a pinning-free interface with charge mobility up to 6000 cm2/Vsec, significantly higher than previous III-V semiconductor-metal oxide systems, suitable for high-performance MOSFETs and other devices, by forming a conducting channel with controlled charge carrier density and mobility.
Implementation Method 1
The use of RF sputtering to grow a dielectric layer on III-V semiconductors in an atmosphere containing inert gases and oxygen
Implementation Method 2
The use of RF sputtering to grow a dielectric layer on III-V semiconductors in an atmosphere containing inert gases and oxygen
Data Source
AI summary
Systems and methods for passivation of III-V semiconductors to create heterogeneous structures based on such semiconductors, to the structures themselves, and to devices using passivated III-V semiconductors, such as metal oxide-semiconductor field effect transistors (MOSFET) and Hall effect sensors using III-V semiconductors.