SiC Low Gain Avalanche Diode (LGAD) for Minimum Ionization Particle (MIP) sensors

Presently Si based for Minimum Ionization Particle (MIP) detectors require very low temperature (<-30 C) for the required level of device performance. DoE-HEP is looking for much faster higher radiation resistance radiation detectors that are capable of operation at higher temperatures, i.e., ones based on SiC substrates for future experiments. Hence design and development efforts SiC based detectors, for single charged particles and MIPs with a primary focus on using thick (50-70 um) epitaxy 4H-SiC n-type layers with low-doping (1013 - 1014 cm-3), are needed to realize ultrafast high radiation resistance high temperature operation. The epi-layer should exhibit low on resistance and low leakage current in the reverse bias condition. Ultimately, low gain avalanche diodes (LGAD) based on SiC need to be developed to replace, the present Si based detectors. The project, submitted under DOE Topic 56 Subtopic 37(a), aims to produce larger area detectors for tracking and new applications with improved radiation tolerance. SiC detectors offer superior radiation resistance and stability, enabling effective detection even after exposure to intense radiation. They are also useful for X-ray and ultraviolet monitoring. The proposed detectors will have fast signal collection and readout capabilities and must withstand ionizing and displacement damage radiation. In Phase II we plan to refine growth parameters for thick epitaxial 4H-SiC n-type layers with low carrier concentrations. In Phase II, low-gain avalanche diode (LGAD) based 4H-SiC detectors will be fabricated. N-type doping will be achieved using nitrogen introduction, and growth conditions will be optimized for large-area wafer production. Optical and structural characterization will assess defect density and crystalline quality, ensuring devices meet HEP requirements for radiation tolerance and performance. In Phase II we will fabricate a full structure SiC LGAD device and sample them to various DoE laboratories for validation and feedback. Our team is uniquely qualified to do this work. Dr. Kannan Vasudevan (P.I.) and Dr. Gary Tompa of SMI, Prof. Michael Spencer (MSU) and Prof. M.V.S. Chandrashekar (USC) form a formidable team with extensive experience in CVD hardware and SiC process among many other technologies. The anticipated public benefits of this work include technical, economic, social, and other public areas as a whole and advancement in science by advancing the capabilities to understand phenomenon at atomic scale resolution leading to new discoveries. This project will advance the high energy physics sector with the development of high-energy particle accelerators, the possibility to study nuclei, quarks, and gauge bosons using the polarized electron sources presented here. Furthermore, the technology helps in enabling basic energy and medical sciences, better understanding of the universe and also for the US to lead the world in cutting edge technology.