Classical and quantum silicon photonics technologies lack a monolithically integrated high-performance silicon-based laser, which is a critical building block for future silicon photonics platforms, as well as applications such as LiDAR and AI. This is because it has not been possible to monolithically integrate lasers made of III-V or II-VI semiconductors into CMOS. Research in direct bandgap GeSn and SiGeSn alloys has been ongoing for more than a decade, but there are still significant problems with material quality and the requirement for a relaxed buffer virtual substrate which complicates integration in a CMOS process.
Silicon and SiGe/SiGeC alloys epitaxially grown on silicon have indirect bandgaps, hence are not suitable for lasers. However, it is possible to engineer materials comprised of Silicon, Germanium and Carbon epitaxially grown directly on silicon substrates, to have direct bandgaps in the Short-Wavelength Infra-Red (SWIR) range. These short period superlattices are engineered at the atomic plane level and consequently have properties that can be very different from the constituent elements. Because they can be epitaxially grown directly on silicon and consist only of elements found in BiCMOS and leading-edge CMOS, the monolithic integration of these superlattices with CMOS is relatively straightforward.
By varying the composition of some atomic planes, group-IV optoelectronic metamaterials can bring a variety of useful non-linear photonic properties to CMOS technology, serving as topological insulators and topological semimetals. In the future, these metamaterials may enable key building blocks for classical and quantum silicon photonics, such as lasers, photodiodes, amplitude and phase modulators, photon energy conversion and entanglement. Other group-IV heterojunction engineered materials and devices will enable room temperature single photon emission and detection, thereby enabling quantum photonic computing at room temperature.
Quantum Semiconductor’s presentation will show results of Density Functional Theory simulations of direct bandgap superlattices and product concepts uniquely enabled by monolithically integrated direct band-gap metamaterials into CMOS.