Design of an ultra-compact electro-absorption modulator comprised of a deposited TiN/HfO_2/ITO/Cu stack for CMOS backend integration

Page view(s)
6
Checked on Dec 26, 2023
Design of an ultra-compact electro-absorption modulator comprised of a deposited TiN/HfO_2/ITO/Cu stack for CMOS backend integration
Title:
Design of an ultra-compact electro-absorption modulator comprised of a deposited TiN/HfO_2/ITO/Cu stack for CMOS backend integration
Journal Title:
Optics Express
Keywords:
Publication Date:
17 July 2014
Citation:
Shiyang Zhu, G. Q. Lo, and D. L. Kwong, "Design of an ultra-compact electro-absorption modulator comprised of a deposited TiN/HfO2/ITO/Cu stack for CMOS backend integration," Opt. Express 22, 17930-17947 (2014) http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-15-17930
Abstract:
An ultra-compact electro-absorption (EA) modulator operating around 1.55-μm telecom wavelengths is proposed and theoretically investigated. The modulator is comprised of a stack of TiN/HfO2/ITO/Cu conformally deposited on a single-mode stripe waveguide to form a hybrid plasmonic waveguide (HPW). Since the thin ITO layer can behave as a semiconductor, the stack itself forms a MOS capacitor. A voltage is applied between the Cu and TiN layers to change the electron concentration of ITO (NITO), which in turn changes its permittivity as well as the propagation loss of HPW. For a HPW comprised of a Cu/3-nm-ITO/5-nm-HfO2/5-nm-TiN stack on a 400-nm × 340-nm-Si stripe waveguide, the propagation loss for the 1.55-μm TE (TM) mode increases from 1.6 (1.4) to 23.2 (23.9) dB/μm when the average NITO in the 3-nm ITO layer increases from 2 × 1020 to 7 × 1020 cm−3, which is achieved by varying the voltage from −2 to 4 V if the initial NITO is 3.5 × 1020 cm−3. As a result, a 1-μm-long EA modulator inserted in the 400-nm × 340-nm-Si stripe waveguide exhibits insertion loss of 2.9 (3.2) dB and modulation depth of 19.9 (15.2) dB for the TE (TM) mode. The modulation speed is ~11 GHz, limited by the RC delay, and the energy consumption is ~0.4 pJ/bit. The stack can also be deposited on a low-index-contrast waveguide such as Si3N4. For example, a 4-μm-long EA modulator inserted in an 800-nm × 600-nm-Si3N4 stripe waveguide exhibits insertion loss of 6.3 (3.5) dB and modulation depth of 16.5 (15.8) dB for the TE (TM) mode. The influences of the ITO, TiN, HfO2 layers and the beneath dielectric core, as well as the processing tolerance, on the performance of the proposed EA modulator are systematically investigated. ©2014 Optical Society of America
License type:
PublisherCopyrights
Funding Info:
Description:
Full paper can be downloaded from the Publisher's URL provided.
ISSN:
1094-4087
Files uploaded:
File Size Format Action
There are no attached files.