Deuterated SiNx: a low-loss, back-end CMOS-compatible platform for nonlinear integrated optics.

Area of Science:

• Materials Science
• Photonics
• Semiconductor Manufacturing

Background:

• Silicon nitride (SiN) is a key material for photonic-integrated circuits (PICs) due to its transparency and CMOS compatibility.
• Existing SiN fabrication methods force a compromise between thermal budget and optical loss.
• Parasitic bonds in hydrogenated SiN cause absorption losses at 1.55 µm.

Purpose of the Study:

• To review recent advancements in deuterated silicon nitride (SiNx:D) for PICs.
• To highlight the benefits of SiNx:D over traditional SiN.
• To explore future potential of SiNx:D in integrated photonics.

Main Methods:

• Fabrication of SiNx:D films using deuterated precursors via plasma-enhanced chemical vapor deposition (PECVD).
• Characterization of optical properties and loss reduction at telecommunication wavelengths.
• Assessment of CMOS fabrication compatibility, including low-temperature, back-end-of-line processes.

Main Results:

• SiNx:D films exhibit significantly reduced absorption losses near 1.55 µm compared to hydrogenated SiN.
• Low-loss PICs are achieved using a low-temperature, CMOS-compatible PECVD process.
• The SiNx:D platform demonstrates potential for both linear and nonlinear photonic applications.

Conclusions:

• Deuterated silicon nitride (SiNx:D) offers a promising route to low-loss PICs.
• This material overcomes limitations of traditional SiN fabrication, enabling simultaneous low loss and low thermal budget.
• SiNx:D is poised to be instrumental in developing highly efficient integrated photonic chips, potentially co-packaged with electronics.