Strain-induced enhancement of plasma dispersion effect and free-carrier absorption in SiGe optical modulators.

The plasma dispersion effect and free-carrier absorption are widely used to change refractive index and absorption coefficient in Si-based optical modulators. However, the weak free-carrier effects in Si cause low modulation efficiency, resulting in large device footprint and power consumption. Here, we theoretically and experimentally investigate the enhancement of the free-carrier effects by strain-induced mass modulation in silicon-germanium (SiGe).

Low-driving-current InGaAsP photonic-wire optical switches using III-V CMOS photonics platform.

Electrically-driven Mach-Zehnder interferometer type InGaAsP photonic-wire optical switches have been demonstrated using a III-V-on-insulator structure bonded on a thermally oxidized Si with an Al(2)O(3)/InP bonding interfacial layer which enables strong wafer bonding and low propagation loss. Lateral p-i-n junctions in the InGaAsP photonic-wire waveguides were formed by using ion implantation for changing refractive index in the InGaAsP waveguide through carrier injection. Optical switching with 10 dB extinction ratio was achieved with driving current of 200 µA which is approximately 10 times smaller than that of Si photonic-wire optical switch owing to larger free-carrier effect in InGaAsP than that in Si.

Initial Processes of Atomic Layer Deposition of Al₂O₃ on InGaAs: Interface Formation Mechanisms and Impact on Metal-Insulator-Semiconductor Device Performance.

Interface-formation processes in atomic layer deposition (ALD) of Al₂O₃ on InGaAs surfaces were investigated using on-line Auger electron spectroscopy. Al₂O₃ ALD was carried out by repeating a cycle of Al(CH₃)₃ (trimethylaluminum, TMA) adsorption and oxidation by H₂O. The first two ALD cycles increased the Al KLL signal, whereas they did not increase the O KLL signal.