SiC Ohmic Contact Formation by Laser Dopant Activation
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Solution Overview
Problem
The existing methods for manufacturing SiC electronic devices require multiple thermal-annealing steps for doping activation and ohmic contact formation, which can lead to misalignment issues and result in devices with high leakage current or non-functional Schottky contacts.
Innovation Solution
A method involving the implantation of dopants in a SiC substrate followed by localized laser heating to form carbon-rich ohmic contacts, such as graphene or graphite layers, which activates the dopants and forms self-aligned ohmic contacts within the implanted regions, eliminating the need for multiple thermal-annealing steps and ensuring precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple thermal-annealing steps are used for doping activation and ohmic contact formation, then dopant activation and contact formation are achieved, but misalignment occurs between implanted regions and ohmic contacts
Solution Approach 1:
The patent combines dopant activation and ohmic contact formation into a single laser annealing step. The laser beam simultaneously activates the implanted dopants and forms the ohmic contacts from the metal layer, eliminating the need for separate thermal annealing steps and preventing misalignment between the two features.
Solution Approach 2:
The metal layer is deposited over the implanted region before the laser annealing step, preparing the material in advance for ohmic contact formation. This preliminary deposition ensures that when the laser annealing occurs, both dopant activation and ohmic contact formation can proceed simultaneously with precise spatial alignment.
2Reliability
If multiple thermal-annealing steps are performed, then doping and contact formation are completed, but manufacturing time increases
Solution Approach 1:
The patent merges two separate thermal annealing processes (doping activation and ohmic contact formation) into a single laser annealing step. This consolidation reduces the total manufacturing cycle time while ensuring both critical functions are achieved through the simultaneous action of the laser beam on the prepared structure.
3Reliability
If traditional thermal annealing is used, then dopants are activated, but ohmic contact formation requires separate processing steps
Solution Approach 1:
The patent replaces traditional thermal field annealing with a laser beam (electromagnetic energy) to simultaneously achieve dopant activation and ohmic contact formation. The laser provides localized, precise energy delivery that enables both processes to occur in one step, simplifying the manufacturing process while improving contact quality through better alignment.
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 approach enhances the manufacturing process by achieving optimal dopant activation and ohmic contact formation, reducing leakage current and ensuring functional Schottky contacts, thereby improving the reliability and performance of SiC electronic devices.
Implementation Method 1
generating a laser beam directed towards the implanted region thereby heating the implanted region to temperatures in the range of 1500° C. and 2600° C.
Implementation Method 2
heating the implanted region to temperatures in the range of 1500° C. and 2600° C.
Implementation Method 3
activating the dopant of the first conductivity type
Data Source
AI summary
A method for manufacturing a SiC-based electronic device, that includes implanting, at a front side of a solid body of SiC having a conductivity of N type, dopant species of P type, thus forming an implanted region that extends in depth in the solid body starting from the front side and has a top surface co-planar with said front side; and generating a laser beam directed towards the implanted region in order to generate heating of the implanted region at temperatures comprised between 1500° C. and 2600° C. so as to form an ohmic contact region including one or more carbon-rich layers, for example graphene and/or graphite layers, in the implanted region and, simultaneously, activation of the dopant species of P type.