Laser-Engineered Silicon: Manufacturing Low Cost Photonic Systems
Lead Research Organisation:
University of Southampton
Department Name: Optoelectronics Research Centre (ORC)
Abstract
Silicon photonics promises to revolutionize modern optoelectronics by allowing for dense integration of components that feature the best optical and electronic functions of the material. In recent years great progress has been made in this area, with many silicon photonic devices now meeting (or exceeding) the performance requirements of state-of-the-art systems. This includes ultra-low loss interconnects as well as high speed optical regenerators, amplifiers, modulators, and detectors, which form the building blocks for photonic circuits. However, to date, much of this progress has been achieved on silicon-on-insulator (SOI) platforms with a thick buried oxide layer, which are largely incompatible with electronic device development, and relatively expensive, thus precluding truly integrated systems from reaching the high-volume market. Consequently, there are still crucial challenges to overcome before the performance benefits of SOI photonics outweigh the costs and design constraints, leaving the door open for alternative platforms to be considered.
In this programme we propose to develop a low cost and low temperature laser materials processing procedure to fabricate high quality polycrystalline semiconductor photonic platforms that will rival the performance of their SOI counterparts. Laser processed polycrystalline materials are already well-established for use in electronic technologies where some performance can be sacrificed in favour of reduced processing costs, for example, in the backplanes of smart phones and televisions. However, if the polycrystalline grains can be grown as large as the individual components, then the optical (and electronic) properties will approach those of the single crystal materials. By building on the platform established by the electronics community, this work seeks to grow large grain polycrystalline materials to realize low loss photonic components. Importantly, the high localization of this laser crystallization procedure directly alleviates issues associated with multi-material and multi-layer photonic device integration, and can also be used to modify or repair the individual components at a late stage in the fabrication, helping to increase the production yield and reduce the costs of integrated systems. Furthermore, this method offers the unique advantage of removing the substrate dependence from semiconductor photonics, thus offering the possibility to extend the application space through the use of substrate materials with enhanced optical functionality, increased transparencies, or even flexible plastics. By reducing costs and barriers associated with device fabrication, our innovative project will set the scene for wide spread use of laser-engineered semiconductor photonic components in mainstream optoelectronic systems.
In this programme we propose to develop a low cost and low temperature laser materials processing procedure to fabricate high quality polycrystalline semiconductor photonic platforms that will rival the performance of their SOI counterparts. Laser processed polycrystalline materials are already well-established for use in electronic technologies where some performance can be sacrificed in favour of reduced processing costs, for example, in the backplanes of smart phones and televisions. However, if the polycrystalline grains can be grown as large as the individual components, then the optical (and electronic) properties will approach those of the single crystal materials. By building on the platform established by the electronics community, this work seeks to grow large grain polycrystalline materials to realize low loss photonic components. Importantly, the high localization of this laser crystallization procedure directly alleviates issues associated with multi-material and multi-layer photonic device integration, and can also be used to modify or repair the individual components at a late stage in the fabrication, helping to increase the production yield and reduce the costs of integrated systems. Furthermore, this method offers the unique advantage of removing the substrate dependence from semiconductor photonics, thus offering the possibility to extend the application space through the use of substrate materials with enhanced optical functionality, increased transparencies, or even flexible plastics. By reducing costs and barriers associated with device fabrication, our innovative project will set the scene for wide spread use of laser-engineered semiconductor photonic components in mainstream optoelectronic systems.
Planned Impact
This proposal promises to transform the next generation of optoelectronic systems by reducing the barriers and costs associated with silicon photonic device fabrication and integration. This research is perfectly aligned with the EPSRC theme "Photonics for Future Systems", and we believe could ultimately have significant economic and societal impact in the areas of ICT, sensing, and manufacturing. In terms of market size, photonics21 (European Public-Private-Partnership) estimates the global market for optical components will be worth 30B euros in 2015, with the EU share approaching 50%.
ICT: The integrated polysilicon photonics platforms developed through our proposed work have the potential to increase the speed and capacity of data transport systems, whilst at the same time lowering the manufacturing costs, reducing energy requirements, and increasing production yields. Importantly, low cost polysilicon photonic components such as interconnects, modulators, and photodetectors, have already been identified by the leading semiconductor company Intel as a key step towards truly realizing the high density integration of optical and electronic devices. We expect that as the technology matures other major computer (IBM) and communication companies (Finisar) will find similar merit.
Sensing: As the laser-engineering process removes many substrate restrictions, there are several material platforms that could be established for use in biological or chemical sensing. For example, cheap, flexible, and disposable sensors developed on plastic substrates could find use as wearable monitoring systems, supporting growth in several markets such as point of care diagnostics and wearable electronics. Alternatively, more robust systems built on germanium-on-sapphire platforms, that offer the potential to operate over the important molecular 'finger-print' spectral region, could be used for rapid (in-field) identification of different types of hazardous chemicals/materials. Thus, the impact of this work could also feed into the EPSRC themes "Healthcare Technologies" and "Global Uncertainties".
Manufacturing: The UK has a strong laser manufacturing industry (e.g., SPI Lasers, Elforlight, Oxford Lasers), and the importance of laser-based manufacturing has been recognised through the establishment of an EPSRC Centre for Innovative Manufacturing in Laser-Based Production Processes (http://www.cim-laser.ac.uk/). Currently one of the major industrial growth markets for Excimer lasers is in materials processing of low cost electronic semiconductor electronic chips, and we can expect that new markets will open up through the expansion of these processing procedures to photonic components and systems. Our partnership with Elforlight and SPI Lasers demonstrates the relevance of our proposal to this sector and their confidence in this technology, even at this early stage. Furthermore, the low energies and temperatures of our process procedures also align with EPSRCs requirements for green, sustainable manufacturing procedures.
The successful outcomes of our proposed work will ultimately help to shift the focus away from single crystal, single layer optoelectronic platforms to more flexible, 3D integrable polysilicon alternatives. As our programme is largely centred on materials optimization, much of the immediate impact is likely to be within the academic community. However, as there is already interest within the industrial community, we expect that the commercial value of this approach will soon be widely recognized. Thus, by training new staff in this emerging area we will ensure that the UK has a solid skill and knowledge base to quickly capitalize on future industrial developments.
ICT: The integrated polysilicon photonics platforms developed through our proposed work have the potential to increase the speed and capacity of data transport systems, whilst at the same time lowering the manufacturing costs, reducing energy requirements, and increasing production yields. Importantly, low cost polysilicon photonic components such as interconnects, modulators, and photodetectors, have already been identified by the leading semiconductor company Intel as a key step towards truly realizing the high density integration of optical and electronic devices. We expect that as the technology matures other major computer (IBM) and communication companies (Finisar) will find similar merit.
Sensing: As the laser-engineering process removes many substrate restrictions, there are several material platforms that could be established for use in biological or chemical sensing. For example, cheap, flexible, and disposable sensors developed on plastic substrates could find use as wearable monitoring systems, supporting growth in several markets such as point of care diagnostics and wearable electronics. Alternatively, more robust systems built on germanium-on-sapphire platforms, that offer the potential to operate over the important molecular 'finger-print' spectral region, could be used for rapid (in-field) identification of different types of hazardous chemicals/materials. Thus, the impact of this work could also feed into the EPSRC themes "Healthcare Technologies" and "Global Uncertainties".
Manufacturing: The UK has a strong laser manufacturing industry (e.g., SPI Lasers, Elforlight, Oxford Lasers), and the importance of laser-based manufacturing has been recognised through the establishment of an EPSRC Centre for Innovative Manufacturing in Laser-Based Production Processes (http://www.cim-laser.ac.uk/). Currently one of the major industrial growth markets for Excimer lasers is in materials processing of low cost electronic semiconductor electronic chips, and we can expect that new markets will open up through the expansion of these processing procedures to photonic components and systems. Our partnership with Elforlight and SPI Lasers demonstrates the relevance of our proposal to this sector and their confidence in this technology, even at this early stage. Furthermore, the low energies and temperatures of our process procedures also align with EPSRCs requirements for green, sustainable manufacturing procedures.
The successful outcomes of our proposed work will ultimately help to shift the focus away from single crystal, single layer optoelectronic platforms to more flexible, 3D integrable polysilicon alternatives. As our programme is largely centred on materials optimization, much of the immediate impact is likely to be within the academic community. However, as there is already interest within the industrial community, we expect that the commercial value of this approach will soon be widely recognized. Thus, by training new staff in this emerging area we will ensure that the UK has a solid skill and knowledge base to quickly capitalize on future industrial developments.
Organisations
- University of Southampton (Lead Research Organisation, Project Partner)
- University of Toronto (Collaboration)
- Royal Institute of Technology (Collaboration)
- HiLASE Centre of the Institute of Physics AS CR (Collaboration)
- IHP Microelectronics GmbH (Collaboration)
- Elforlight (United Kingdom) (Project Partner)
- Diamond Light Source (Project Partner)
- University of Glasgow (Project Partner)
- Echerkon Technologies Ltd (Project Partner)
- TRUMPF (United Kingdom) (Project Partner)
Publications
Reed G
(2015)
Facilitating an integrated Silicon Photonics platform
Peacock A
(2015)
Semiconductor optical fibers
Peacock A
(2016)
Semiconductor fibres for infrared nonlinear photonics
Healy N
(2016)
CO 2 Laser-Induced Directional Recrystallization to Produce Single Crystal Silicon-Core Optical Fibers with Low Loss
in Advanced Optical Materials
Coucheron DA
(2016)
Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres.
in Nature communications
Gardes F
(2016)
Group IV compounds for integrated photonic applications
Peacock A
(2016)
Crystalline core silicon fibers for optoelectronic applications
Peacock A
(2016)
Towards in-fiber silicon photonics
Song S
(2017)
GaSb-core optical fibers
Description | This proposal seeks to establish laser-engineered silicon photonic components as low cost solutions for use in highly integrated optoelectronic systems. The components are first deposited in an amorphous form, using a low cost and low temperature process, before being processed with a laser to convert it into crystalline silicon. The procedure is highly localized and so can be used to individually tune the properties of different components within an integrated circuit. Most of our work to date has focused on optimizing the laser processing parameters to achieve high quality single-crystal like silicon waveguides with micro/nanoscale dimensions. So far we have managed to produce silicon waveguides that are composed of single-crystal grains with lengths on the order of a few millimetres, so that each waveguide consists of only a few grains. The corresponding transmission losses have been measured to be as low as ~4 dB/cm, which is lower than any previously reported values for silicon waveguides of this type. As a result, this has opened a route to the first demonstration of nonlinear propagation in this material system, which is an important step towards the development of components that can be used for high speed, all-optical signal processing. More recently we have extended this work to laser processing silicon-germanium alloys where, as well as being able to crystallise the starting amorphous material, we can also use the heat treatment to tune the material composition to write waveguides and functional components, such as gratings, directly in to the films. We are also investigating the possibility to strain engineer the alloy materials for the development of integrated light sources. The findings from this research will ultimately pave the way to the realization of highly functional photonic circuits that could, in future, be directly integrated with electronic layers to realize a complete optoelectronic chip. |
Exploitation Route | We expect that this waveguide fabrication method will be adopted by other researchers working in this area, and could even be employed in silicon photonics industries when the process is optimized. |
Sectors | Digital/Communication/Information Technologies (including Software) Electronics Manufacturing including Industrial Biotechology |
Description | The laser processing procedures developed in this grant have been applied to modify, trim and tune individual components within integrated silicon photonic systems. They have also been applied to programme circuits after fabrication and for testing of individual components by removing coupling ports. These applications are particularly useful for improving the yields and reliability of integrated photonic chips, thus reducing the costs. This work also led to a collaboration with an industrial partner to write optical circuits into specially grown wafers. There is also interest in using this approach to optimize the connections between active and passive silicon photonic components, which are typically characterized by different waveguide sizes, to enable the production of highly functional optoelectronic circuits. |
First Year Of Impact | 2018 |
Sector | Digital/Communication/Information Technologies (including Software) |
Impact Types | Economic |
Description | EPSRC Research Fellowship |
Amount | £1,150,136 (GBP) |
Funding ID | EP/P000940/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 02/2017 |
End | 02/2022 |
Description | Electronic-Photonic Convergence: A Platform Grant |
Amount | £1,477,730 (GBP) |
Funding ID | EP/N013247/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 03/2016 |
End | 03/2022 |
Description | Silicon core fibres: extending the reach of nonlinear fibre systems |
Amount | £927,721 (GBP) |
Funding ID | EP/Y008308/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2024 |
End | 04/2027 |
Title | Dataset for Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si-Ge Nanoscale Thin Films |
Description | Dataset supports: Aktas, Ozan, Oo, Swe, MacFarquhar, Stuart, James, Mittal, Vinita, Chong, Harold and Peacock, Anna(2020). Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si-Ge Nanoscale Thin Films. ACS Applied Materials & Interfaces. DOI: http://dx.doi.org/10.1021/acsami.9b22135 |
Type Of Material | Database/Collection of data |
Year Produced | 2020 |
Provided To Others? | Yes |
Impact | Data set led to the publication of the paper: Laser-Driven Phase Segregation and Tailoring of Compositionally Graded Microstructures in Si-Ge Nanoscale Thin Films. ACS Applied Materials & Interfaces. DOI: http://dx.doi.org/10.1021/acsami.9b22135 |
URL | https://doi.org/10.5258/SOTON/D1213 |
Title | Dataset for Non-Isothermal Phase-Field Simulation of Laser-Written In-Plane SiGe Heterostructures for Photonic Applications |
Description | Data set for paper entitled: Non-Isothermal Phase-Field Simulation of Laser-Written In-Plane SiGe Heterostructures for Photonic Applications |
Type Of Material | Database/Collection of data |
Year Produced | 2021 |
Provided To Others? | Yes |
Impact | This data set led to the publication of the paper Non-Isothermal Phase-Field Simulation of Laser-Written In-Plane SiGe Heterostructures for Photonic Applications in the journal Nature: Communications Physics |
Title | Dataset for the journal paper titled "Low-temperature polycrystalline silicon waveguides for low loss transmission in the near-to-mid-infrared region" |
Description | This dataset supports the publication: Amar N. Ghosh, Stuart J. MacFarquhar, Ozan Aktas, Than S. Saini, Swe Z. Oo, Harold M. H. Chong, and Anna C. Peacoc (2022) Low-temperature polycrystalline silicon waveguides for low loss transmission in the near-to-mid-infrared region. Optics Express. The excel file contains all experimental data used for generating Fig.3 and Fig.6. |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | Resulted in the published paper: "Lowtemperature polycrystalline silicon waveguides for low loss transmission in the near-to-mid-infrared region," Opt. Express v31, 1532 (2023). |
URL | https://eprints.soton.ac.uk/id/eprint/472512 |
Description | Collaboration on laser processing of SiGe material platforms |
Organisation | IHP Microelectronics GmbH |
Country | Germany |
Sector | Private |
PI Contribution | We have been laser processing the SiGe wafers to investigate direct writing of optical components within the wafers. |
Collaborator Contribution | IHP have provided us with several SiGe wafers for use in our laser materials processing work. They have also done some development work to deposit materials at our desired thickness and characterised the samples. |
Impact | N/A |
Start Year | 2019 |
Description | Collaboration on low cost integrated photonic platforms |
Organisation | University of Toronto |
Country | Canada |
Sector | Academic/University |
PI Contribution | N/A |
Collaborator Contribution | Prof J. S. Aitchison is providing guidance to our work on the development of novel material integrated platforms. |
Impact | We have obtained one funded grant with University of Toronto as our partners. Several papers have been produced as a result of the advice we have received from this team. |
Start Year | 2015 |
Description | Collaboration on silicon fibre fabrication with a laser furnace |
Organisation | Royal Institute of Technology |
Country | Sweden |
Sector | Academic/University |
PI Contribution | We have been characterizing the optical properties of silicon core fibres produced using a laser furnace. |
Collaborator Contribution | The KTH team have been supplying silicon core fibres produced from their draw tower where the heating element is a CO laser. This enables more control of the heating of the silicon core to reduce the impurities during the drawing. |
Impact | None yet, but there will be publications over the coming year. |
Start Year | 2023 |
Description | Collaboration regarding modelling of laser-materials interactions |
Organisation | HiLASE Centre of the Institute of Physics AS CR |
Country | Czech Republic |
Sector | Academic/University |
PI Contribution | We have produced a number of samples fabricated via laser crystallization for them to model and compare with our experimental results. |
Collaborator Contribution | They have modelled our experimental findings, helping us to understand the light-matter interactions in our material. |
Impact | We have produced one nature materials paper from this collaboration to date, and have had two grant proposals funded, on which they are a partner institute. This collaboration is multi-disciplinary as it combines experimental laser physics with computational physics. |
Start Year | 2015 |
Description | Royal Society Meeting - Frontiers in Science |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | Around 30 early career researchers in both the natural and social sciences attended a 3 day meeting. All presentations were recorded and posted on the Royal Society's website. |
Year(s) Of Engagement Activity | 2016 |
Description | SPIE Visiting Lecturer - University of Auckland |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | I was a visiting lecturer for the SPIE student chapter at the University of Auckland. I gave a lecture the described my career progression and how this linked to my current research interests, which sparked questions and discussions afterwards. |
Year(s) Of Engagement Activity | 2017 |