NSUF 25-5208: Investigating Ultraviolet Sensitive Avalanche Photodiodes by Ion Implantation in 4H-Silicon Carbide for High Temperature Sensing

High temperature and radiation are an ever-present challenge faced when deploying sensors and instrumentation in advanced nuclear reactors and fuel cycles. However, wide-bandgap semiconductor materials, such as 4H-silicon carbide (SiC), have demonstrated survivability in these environments. The wide-bandgap nature in such materials is critical in the formation of electronic barriers that reduce the impact of temperature derived electronic noise. Also, the greater dislocation energy associated with wide-bandgap material aids in reducing the formation of defects by incident high radiation fields and may extend the service life of sensors in such fields. p-n diodes will be fabricated for radiation sensing by ion-implanting high purity 4H-SiC epitaxial layers at the Michigan Ion Beam Laboratory. SiC samples will be irradiated by aluminum ions to implant acceptors near the surface of the epitaxial layer. Heating the samples during irradiation will assist in reducing the amount of damage to the crystal lattice resulting from scattering/recoil. Annealing the samples to high temperatures post irradiation will activate the aluminum acceptors and repair damage to the crystal lattice. p-n diode will be realized by depositing nickel metal to form ohmic contacts with the semiconductor. Contacts of various sizes will be formed to optimize the sensor design. In addition to high temperature and radiation tolerance, wide-bandgap semiconductor 4H-SiC is also sensitive to ultraviolet (UV) light while being blind to light in the visible spectrum. Thus, contacts will also be designed with optical windows for UV photon detection. Electrical characterization of the devices will be performed using traditional current-voltage and capacitance-voltage profiling techniques. Radiation sensitivity of the devices may also be determined by measuring the response from alpha particle and x-ray irradiation. Device characterization and performance may also be measured with respect to temperature to demonstrate applicability to high temperature environments. The high purity nature of the epitaxial layers implies the devices should have a high breakdown voltage and reduced critical electrical field, indicating the devices would be suitable for signal multiplication by avalanche breakdown. Thus, at high biases the devices may be operated as avalanche photodiodes (APD) when paired with a suitable quenching circuit. As such, a complete demonstration of UV sensitive SiC APDs may be achieved. In addition to designing a photodiode sensitive to UV light, outside the range of conventional silicon-based photodiodes, SiC APDs may also be operated in high temperature and radiation environments, previously inaccessible to silicon-based technologies.

Informações Adicionais

Campo	Valor
Award Announced Date	2025-08-06T10:05:41.3
Awarded Institution	The Ohio State University
Facility Tech Lead	Kevin Field
Irradiation Facility	Michigan Ion Beam Laboratory
PI	Lei (Raymond) Cao
PI Email	[email protected]
Project Type	RTE
RTE Number	None