SiC MOSFET Getter Layers for BTI Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Silicon carbide semiconductor devices are susceptible to Bias-Temperature Instability (BTI) and premature failure due to interactions with chemical species, which affect device performance and stability, especially under high-temperature and high-power conditions.
Innovation Solution
Incorporating a getter material, such as titanium silicide or titanium silicide carbide, to immobilize chemical species like hydrogen and water, reducing their impact on device performance by forming ohmic contacts and using additional getter materials like Ti/TiN to create a chemical barrier and improve device stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If silicon carbide devices operate at high temperature and high power, then device performance and capability are improved, but susceptibility to chemical species interaction increases causing BTI and premature failure
Solution Approach 1:
A getter layer is introduced as an intermediary material between the SiC device and chemical species in the environment. This getter layer selectively absorbs or reacts with harmful chemical species (such as hydrogen, water vapor, or other contaminants) before they can interact with the SiC device, thereby protecting the device while allowing it to operate at high temperature and power conditions.
Solution Approach 2:
The getter layer creates a protective environment around the SiC device by maintaining a chemically inert interface. By continuously absorbing or neutralizing reactive chemical species, the getter layer effectively creates a localized inert atmosphere that prevents unwanted chemical reactions between the environment and the device, enabling reliable high-temperature operation.
2Reliability
If getter material is added to protect against chemical species, then device reliability is improved, but device structure complexity increases
Solution Approach 1:
The getter layer is implemented as a thin film structure that can be deposited conformally on the SiC device surface. This thin film approach provides effective chemical protection while minimizing the additional structural complexity and maintaining compatibility with existing device packaging and interconnection structures.
Solution Approach 2:
The solution employs composite material structures combining the SiC device with a getter layer material that has complementary properties. The getter layer material is selected to have appropriate thickness, porosity, and chemical reactivity characteristics that work synergistically with the SiC device to provide enhanced reliability without excessive structural 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
The getter material effectively reduces the impact of chemical species on silicon carbide semiconductor devices, enhancing stability and preventing premature failure by immobilizing and blocking chemical species, thereby improving device performance and reliability.
Implementation Method 1
a getter material, such as titanium silicide or titanium silicide carbide, to immobilize chemical species like hydrogen and water
Data Source
AI summary
Semiconductor devices comprising a getter material are described. The getter material can be located in or over the active region of the device and/or in or over a termination region of the device. The getter material can be a conductive or an insulating material. The getter material can be present as a continuous or discontinuous film. The device can be a SiC semiconductor device such as a SiC vertical MOSFET. Methods of making the devices are also described. Semiconductor devices and methods of making the same comprising source ohmic contacts formed using a self-aligned process are also described. The source ohmic contacts can comprise titanium silicide and/or titanium silicide carbide and can act as a getter material.