Hydrogen-free low-temperature silica for next generation integrated photonics

Fuente: arXiv
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Main Authors: Qiu, Zheru, Li, Zihan, Wang, Rui Ning, Ji, Xinru, Divall, Marta, Siddharth, Anat, Kippenberg, Tobias J.
Format: Preprint
Published: 2023
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author Qiu, Zheru
Li, Zihan
Wang, Rui Ning
Ji, Xinru
Divall, Marta
Siddharth, Anat
Kippenberg, Tobias J.
author_facet Qiu, Zheru
Li, Zihan
Wang, Rui Ning
Ji, Xinru
Divall, Marta
Siddharth, Anat
Kippenberg, Tobias J.
contents The advances in novel low-loss "on insulator" integrated photonics platforms beyond silicon, such as thin-film LiNbO3, LiTaO3, GaP and BaTiO3 have demonstrated major potential across a wide range of applications, due to their unique electro-optical or nonlinear optical properties. This has heralded novel devices, ranging from low-voltage and high-speed modulators to parametric amplifiers. For such photonic integrated circuits, a low-loss SiO2 cladding layer is a key element, serving as a passivation layer for the waveguides and enabling efficient fiber-to-chip coupling. However, numerous novel ferroelectric or III-V "on insulator" platforms have low tolerances for process temperature. This prohibits using high-temperature anneals to remove hydrogen, a common impurity that is inherent to ordinary chemical vapor deposited SiO2 and causes significant optical loss in the near infrared. Here, we satisfy the dichotomy of a low-loss wafer scale manufactured SiO2 cladding and low processing temperature. Inspired by the manufacturing of optical fibers, we introduce a hydrogen-free, low-loss SiO2 cladding that is deposited at low temperatures (300 degrees Celsius) by using SiCl4 and O2 as precursors in inductively coupled plasma-enhanced chemical vapor deposition (ICPCVD). By replacing hydrogenous silicon precursors (e.g. SiH4) with SiCl4, the deposited film is inherently free from residual hydrogen. The process temperature is compatible with the "on insulator" platforms and CMOS electronic integrated circuits. We demonstrate a wide low-loss window that covers all telecommunication bands from 1260 nm to 1625 nm. We achieve a < 2.5 dB/m waveguide loss at 1550 nm, comparable with 1200 degree Celsius annealed films. Our SiCl4 process provides a key future cladding for all recently emerged "on-insulator" photonics platforms, that is low cost, scalable in manufacturing, and directly foundry compatible.
format Preprint
id arxiv_https___arxiv_org_abs_2312_07203
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hydrogen-free low-temperature silica for next generation integrated photonics
Qiu, Zheru
Li, Zihan
Wang, Rui Ning
Ji, Xinru
Divall, Marta
Siddharth, Anat
Kippenberg, Tobias J.
Optics
Applied Physics
The advances in novel low-loss "on insulator" integrated photonics platforms beyond silicon, such as thin-film LiNbO3, LiTaO3, GaP and BaTiO3 have demonstrated major potential across a wide range of applications, due to their unique electro-optical or nonlinear optical properties. This has heralded novel devices, ranging from low-voltage and high-speed modulators to parametric amplifiers. For such photonic integrated circuits, a low-loss SiO2 cladding layer is a key element, serving as a passivation layer for the waveguides and enabling efficient fiber-to-chip coupling. However, numerous novel ferroelectric or III-V "on insulator" platforms have low tolerances for process temperature. This prohibits using high-temperature anneals to remove hydrogen, a common impurity that is inherent to ordinary chemical vapor deposited SiO2 and causes significant optical loss in the near infrared. Here, we satisfy the dichotomy of a low-loss wafer scale manufactured SiO2 cladding and low processing temperature. Inspired by the manufacturing of optical fibers, we introduce a hydrogen-free, low-loss SiO2 cladding that is deposited at low temperatures (300 degrees Celsius) by using SiCl4 and O2 as precursors in inductively coupled plasma-enhanced chemical vapor deposition (ICPCVD). By replacing hydrogenous silicon precursors (e.g. SiH4) with SiCl4, the deposited film is inherently free from residual hydrogen. The process temperature is compatible with the "on insulator" platforms and CMOS electronic integrated circuits. We demonstrate a wide low-loss window that covers all telecommunication bands from 1260 nm to 1625 nm. We achieve a < 2.5 dB/m waveguide loss at 1550 nm, comparable with 1200 degree Celsius annealed films. Our SiCl4 process provides a key future cladding for all recently emerged "on-insulator" photonics platforms, that is low cost, scalable in manufacturing, and directly foundry compatible.
title Hydrogen-free low-temperature silica for next generation integrated photonics
topic Optics
Applied Physics
url https://arxiv.org/abs/2312.07203