Abstract
Silicon nitride films with the best optical quality can be realized with low pressure chemical vapor deposition (LPCVD) [1]. However, high mechanical stress within the LPCVD silicon nitride films leads to formation of cracks and prevents thick films (> 400 nm) with high optical quality. A number of clever processes have been developed in order to prevent cracks, such as patterning of crack barriers, multi-step deposition and a Damascene process that deposits silicon nitride into trenches. In addition, to reduce material losses and achieve ultralow propagation losses (~1 dB/m), long-time high temperature annealing (1200 °C for 3 hours) is needed, which can cause dopant diffusion and damage of prefabricated temperature-sensitive devices. Hence, LPCVD Si3N4 is very challenging for applications in back-end-of-line processes and foundry compatible processes. In recent years, low-temperature deposited Si3N4 thin films have attracted increasing interest for 3D hybrid integration of Si3N4 with other materials. Here we report the fabrication of ultralow-loss Si3N4 photonics film by reactive sputtering at room temperature [2]. Directly after room-temperature sputtering, the Si3N4 film loss is 32 dB/m without thermal annealing and the intrinsic optical quality factor (Q) of the fabricated microresonators is 1.1 million in the L-band. This propagation loss is already lower than that of annealing-free LPCVD Si3N4 film deposited at 780 °C [3].
© 2023 IEEE
PDF ArticleMore Like This
Andreas Frigg, Andreas Boes, Guanghui Ren, Duk-Yong Choi, Silvio Gees, and Arnan Mitchell
ce_p_38 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2019
Victor Torres-Company, Zhichao Ye, Ping Zhao, Magnus Karlsson, and Peter A. Andrekson
W4J.3 Optical Fiber Communication Conference (OFC) 2022
Xinru Ji, Rui Ning Wang, Zheru Qiu, and Tobias J. Kippenberg
ce_8_2 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2023