To meet the high radiation challenge for detectors in future high-energy physics, a novel 3D 4H-SiC detector was investigated. Three-dimensional 4H-SiC detectors could potentially operate in a harsh radiation and room-temperature environment because of its high thermal conductivity and high atomic displacement threshold energy. Its 3D structure, which decouples the thickness and the distance between electrodes, further improves the timing performance and the radiation hardness of the detector. We developed a simulation software—RASER (RAdiation SEmiconductoR)—to simulate the time resolution of planar and 3D 4H-SiC detectors with different parameters and structures, and the reliability of the software was verified by comparing the simulated and measured time-resolution results of the same detector. The rough time resolution of the 3D 4H-SiC detector was estimated, and the simulation parameters could be used as guideline to 3D 4H-SiC detector design and optimization.

AC-Coupled LGAD (AC-LGAD) is a new 4D detector developed based on the Low Gain Avalanche Diode (LGAD) technology, which can accurately measure the time and spatial information of particles. The Institute of High Energy Physics (IHEP) designed a large-size AC-LGAD with a pitch of 2000 μm and AC pad of 1000 μm, and explored the effect of N+ layer dose on the spatial resolution and time resolution. The spatial resolution varied from 36 μm to 16 μm depending on N+ dose for a charge corresponding to about 12 minimum ionizing particles. The jitter component of the time resolution does not change significantly with different N+ doses, and it is about 15-17 ps measured by laser. The AC-LGAD with a low N+ dose has a large attenuation factor and better spatial resolution in the central region between pads. In these specific conditions, large signal attenuation factor and low noise level are beneficial to improve the spatial resolution of the AC-LGAD sensor.

AC-Coupled Low Gain Avalanche Diodes (AC-LGADs) are a new type of silicon sensors which conceived for experiments at future colliders. As an evolution of the standard Low Gain Avalanche Diodes (LGADs), AC-LGADs have similar fast timing performance. The innovation is that AC-LGADs are available to provide fine temporal and spatial resolution simultaneously, thanks to two key features: AC-coupled readout through the dielectric layer and a continuous resistive n+ implant. The Institute of High Energy Physics (IHEP) High-Granularity Timing Detector group is developing its first version of AC-LGAD sensors. This paper present the impact of following parameters on AC-LGAD sensor performance: n+ dose, dielectric material and thickness, pad/pitch ratio and the distance between pad and cathode. All data are obtained from 2D Technology Computer-Aided Design (TCAD) simulations. The simulations will benefit future design and optimization.