Integration of III-Sbs with the Si technology

Staff: E. Tournié, L. Cerutti, J.B. Rodriguez

PhD students: K. Madiomanana (2011 – 2015); A. Castellano (CIFRE Alcatel-Lucent, 2013 – 2016); J. Tournet (ITN, 2015 – 2018); M. Rio Calvo (2017 – 2020)

Projects: OPTOSi (ANR blanc 2012 – 2016), MOREMIR (ANR P2N 2013 – 2016), ANTIPODE (ANR, 2014 – 2018), PROMIS (H2020 Marie Curie 2015 – 2018).

Other collaborations: G. Roelkens, U.Ghent, (Belgium); A. Trampert, Paul-Drude-Inst., Berlin (Germany).

The 21st Century is characterized by the explosion of requests for computing, storage and communication capabilities. Global internet traffic grows ~50%/year. A significant part of the total electricity consumption in the World arises from the ICT industry. Replacing electrical interconnects by optical links at various levels (on-chip, from chip to chip, rack to rack,..) is seen by the industry majors as a promising way to keep satisfying the increasing bandwidth demand while decreasing the ICT energy footprint. On another ground, integrating mid-IR devices on Si platform opens the way to the development of miniaturized bio-chemical sensors.

The most mature approach today to integrate III-Vs on Si is the heterogeneous integration. III-V heterostructures are first grown on their native substrates before being bonded as individual dies or as a whole wafer onto the Si platform. Still, on a longer term large scale integration of photonic circuits will more surely rely on the direct epitaxial growth of III-Vs on Si, i.e. the monolithic integration of optoelectronic devices on silicon as put forward on the road map of all electronics majors.

NanoMIR is active in the two approaches, heterogeneous and monolithic integration, with more effort however toward monolithic integration.

Regarding heterogeneous integration, we design and grow dedicated III-Sb mid-IR lasers and photodetectors to be heterogeneously integrated on CMOS compatible platforms for miniaturized gas or bio-sensors. Integration is performed by U. Ghent or by INL Lyon and CEA-LETI, depending on the project. Spectrometers or wavelength meters have already been fabricated in collaboration with U. Ghent (Fig. 1).

nanoMIR photodetection

Fig. 1: (a) Layer stack used for the integrated photodetectors. (b) Schematic of the grating assisted coupling mechanism. (c) SEM cross-section of the photodiode (from Ryckeboer et al., Opt. Express 21, 6101 (2013)).

Regarding monolithic integration, we investigate the direct growth of III-Sb compounds on Si substrates. We have demonstrated cw operation of mid-IR lasers emitting near 2 µm (Fig. 2). In the framework of the OPTOSi project we have developed the integration of III-Sb lasers for emission in the telecom wavelength range near 1.5 µm. The 1.5 µm lasers have been first optimized on their native GaSb substrates and cw operation of monolithically grown 1.55 µm lasers has been demonstrated (Fig. 3). growth on Si. In parallel, the structural and electronic properties of the III-Sb/Si heterostructures are studied in details together with our partners.

nanoMIR III-Sbs with the Si technology

In another field, we are interested in III-V-on-Si solar cells for concentrated photovoltaics. The first part of the project deals with optimizing the cell on its native GaSb substrate before integration on Si.

More details can be found in the related publications.