Achieving near 100% Fill factor for small pixel LGADs: Study of First Trench Isolated LGADs fabricated at Micron Semiconductor Ltd

Abstract This paper presents the development and characterization of Trench-Isolated LGADs (TI-LGADs). This architecture replaces traditional junction termination structures with narrow trenches to minimize inter-pixel distance (IPD) and enhance fill factor (FF). Fabricated by Micron Semiconductor Ltd., TI-LGADs demonstrate excellent electrical isolation, low leakage currents, and no premature breakdown up to 1000 V. Transient Current Technique (TCT) measurements and TCAD simulations reveal an IPD of less than 5 μ m , a significant improvement over standard LGADs which have an IPD of ≈ 50 μ m . The devices exhibit a gain of 2–3, consistent with simulations, and maintain good pixel isolation with minimal crosstalk. These results highlight the potential of TI-LGADs for fine-segmented, high-resolution 4D tracking applications, paving the way for future optimizations and radiation-hard designs.