Hydrogenated amorphous silicon phase-change device based on a p-i-p waveguiding configuration

Effective electro-optical modulation is demonstrated in an hydrogenated amorphous silicon (a-Si:H) based p-i-p waveguiding structure with a core thickness of 2 µm. The phase modulation is studied in particular in a Fabry-Perot resonator through which the voltage-length product for inducing a phase variation Δϕ=π in a travelling wave at λ=1550 nm is determined to be 26 V×cm in both DC and dynamic conditions. The device is fabricated on a silicon substrate by Plasma Enhanced Chemical Vapour Deposition (PECVD) at low temperature (TMAX=120 °C) ensuring an easy back-end integration with CMOS.