SiC MOSFET with Integrated Schottky Diode for Temperature Sensing
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Solution Overview
Problem
Existing silicon carbide (SiC) semiconductor devices lack a specific configuration and method for fabricating a Schottky diode (SBD) to effectively measure the temperature of SiC semiconductor elements.
Innovation Solution
An SiC semiconductor device is designed with an n-type SiC epitaxial substrate, an n-type SiC drift layer, and a Schottky diode formed on the substrate, including an n-type cathode region, a p-type well region, and specific electrode structures for temperature measurement, along with a method involving ion implantation and thermal oxidation to create the necessary regions and contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Schottky diode is formed on SiC epitaxial substrate for temperature measurement, then temperature measurement capability is improved, but device complexity increases
Solution Approach 1:
The Schottky diode structure is integrated onto the SiC epitaxial substrate alongside the MOSFET, allowing the same substrate to serve both power switching and temperature sensing functions. This multi-functional approach enables temperature measurement capability without requiring separate dedicated substrates or sensors.
Solution Approach 2:
The fabrication process merges the formation of the Schottky diode (for temperature measurement) and the MOSFET (for power switching) into a single integrated device structure on the same SiC epitaxial substrate, reducing overall system complexity while achieving both functions.
2Productivity
If common fabrication processes are used for both SBD and MOSFET, then productivity is improved, but manufacturing precision may deteriorate
Solution Approach 1:
The fabrication process is segmented into distinct stages: first forming the MOSFET structure, then selectively forming the Schottky diode structure in specific regions. This segmentation allows each component to be optimized independently while using the same base fabrication processes, maintaining precision while improving productivity.
Solution Approach 2:
Different regions of the SiC epitaxial substrate are given different dopant concentrations and structures tailored to their specific functions: the MOSFET region receives appropriate doping for power switching, while the Schottky diode region is doped to form the metal-semiconductor junction for temperature sensing. This local optimization maintains manufacturing precision despite using common fabrication processes.
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 solution provides an SiC semiconductor device equipped with an SBD for accurate temperature measurement of SiC semiconductor elements, enhancing productivity through common processes for both SBD and MOSFET fabrication and effectively suppressing switching noise.
Implementation Method 1
a first p-type well region formed so as to surround peripheries of the cathode region and the cathode contact region within the SiC drift layer
Implementation Method 2
a first titanium electrode formed on the cathode region, the first titanium electrode serving as a Schottky electrode
Data Source
AI summary
A silicon carbide semiconductor device including an SBD measuring a temperature of a silicon carbide semiconductor element. The silicon carbide semiconductor device includes a MOSFET formed on a silicon carbide epitaxial substrate, and an SBD section measuring a temperature of the MOSFET. The SBD section includes an n-type cathode region in a surface portion of a silicon carbide drift layer; an anode titanium electrode formed on the cathode region, the electrode serving as a Schottky electrode; an n-type cathode contact region of a higher concentration than that of the cathode region, formed in the surface portion of the silicon carbide drift layer to make contact with the cathode region; a cathode ohmic electrode formed on the cathode contact region; and a first p-type well region formed within the silicon carbide drift layer to surround peripheries of the cathode region and the cathode contact region.