SiC MOSFET Interface Termination for Carrier Mobility
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Solution Overview
Problem
The mobility of carriers in silicon carbide-based metal oxide semiconductor field effect transistors (MOSFETs) is reduced due to interface states between the silicon carbide layer and the gate insulating layer, which affects the device's performance and reliability.
Innovation Solution
Incorporating a termination element with four-fold or five-fold coordinated atoms, such as phosphorus and oxygen, in the interface region between the silicon carbide layer and the gate insulating layer to stabilize the interface and improve carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silicon carbide is used to form MOSFET, then breakdown field strength and thermal conductivity are improved, but carrier mobility is reduced due to interface states
Solution Approach 1:
The patent introduces a termination layer comprising nitrogen atoms and/or phosphorus atoms at the interface between the silicon carbide layer and the oxide insulating layer. This intermediary layer acts as a mediator that passivates dangling bonds and reduces interface states, thereby improving carrier mobility while preserving the high breakdown field strength and thermal conductivity characteristics of silicon carbide
Solution Approach 2:
The patent modifies the chemical composition and structure of the interface region by incorporating specific termination elements (nitrogen and/or phosphorus) with defined concentration ratios. By changing the atomic composition parameters at the interface, the patent reduces interface states and improves carrier mobility without compromising the inherent advantages of silicon carbide
2Reliability
If termination element is introduced to reduce interface state, then carrier mobility is improved, but device complexity increases
Solution Approach 1:
The patent applies the termination layer specifically at the critical interface region between the silicon carbide layer and the oxide insulating layer, rather than throughout the entire device structure. This localized approach improves carrier mobility at the interface without unnecessarily complicating other parts of the device
Solution Approach 2:
The patent creates a composite interface structure by combining silicon carbide, oxide insulating layer, and a termination layer containing nitrogen and/or phosphorus atoms. This composite structure leverages the beneficial properties of each material while mitigating their individual drawbacks, particularly the interface state problem
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 termination element effectively reduces phonon scattering and enhances carrier mobility, leading to improved reliability and performance of the MOSFET by stabilizing the interface and removing dangling bonds, thus improving the device's operational efficiency.
Implementation Method 1
The termination element effectively reduces phonon scattering and enhances carrier mobility
Data Source
AI summary
A semiconductor device according to an embodiment includes a silicon carbide layer, an insulating layer, and a region provided between the silicon carbide layer and the insulating layer, the region including a plurality of first atoms of one element from the group consisting of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Si), at least some of the plurality of first atoms being four-fold coordinated atoms and/or five-fold coordinated atoms.