Delta-doped diamond structures for high performance electronic devices

Lead Research Organisation: University College London
Department Name: London Centre for Nanotechnology

Abstract

The combination of extreme electronic and thermal properties found in synthetic diamond produced by chemical vapor deposition (CVD) is raising considerable excitement over its potential use as a semiconductor material. Experimental studies have demonstrated charge-carrier mobilities of >3000cm2V-1s-1 and thermal conductivities >2000 Wm-1K-1. The material has been predicted to have a breakdown field strength in excess of 10 MVcm-1. These figures suggest that, providing a range of technical challenges can be overcome, diamond would be particularly well suited to operation as a semiconductor material wherever high frequencies, high powers, high temperatures or high voltages are required. This proposal addresses the novel use of 'delta-doping' to realise such devices.In conventional device technology a major limitation to the magnitude of mobility values within a given semiconductor is the presence of ionised impurities which cause carrier scattering. However, it is these ionised impurities that are the origin of the free carriers within n- or p-doped material. It is the physical separation of the impurities from the free carriers, such that less scattering occurs and mobility values increase, that lies at the heart of recent improvements in high frequency device performance using III-V semiconductor technology. One approach to achieve this the formation of very thin, highly doped regions within a homostructure. Provided the doped, or d, layer is only a few atom layers thick, carriers will move in a region close to, but outside, this layer. The resultant separation between carriers and the donor/acceptor atoms that created them leads to enhanced mobility. The advantages offered by d doping in other systems will be valid for diamond, with the additional feature that the problem with the large activation energy of boron can be overcome, as very high concentrations are desirable in the d-layer. However, the molecular beam epitaxy (MBE) techniques that can be used for III-V semiconductor growth cannot be used with diamond; the need to use plasma-enhanced CVD processes significantly complicates the approach needed to realise atomic-scale modulation-doped diamond structures.While Si and GaAs devices dominate the solid-state microwave device market, they cannot match the power performance of the vacuum tube. One driver for diamond as a semiconductor stems from an interest in replacing vacuum tubes in niche applications. The development of a solid-state alternative would have many benefits including small size, low weight, low operational voltage (compared with vacuum tube devices), and greater robustness. Current vacuum tube designs, such as magnetrons, klystrons, and traveling-wave tubes (TWT) are usually bulky, often fragile, and expensive (with the exception of magnetrons for microwave ovens, which are manufactured in huge volumes and cost only $10-20/kW). If the intrinsic properties of diamond could be fully exploited through novel delta-doped device design and fabrication, it could compete not only with existing wide-bandgap devices (based on SiC and GaN) but also with TWTs in the entire radio frequency (RF) generation market up to 100 GHz. The control of power at high voltages is another potential use of the diamond devices that may arise from the proposed programme of study. Theoretically, a single diamond switch could be used to switch power at voltages approaching 50 kV. This is not currently achievable with any other electronic material.

Planned Impact

Communications and engagement The identified beneficiaries for this programme, such as Diamond Microwave Devices Ltd and Element Six Ltd, have been actively engaged in a 'pump-priming' capacity prior to the development of this proposal. For example: DMD Ltd awarded UCL a 9 month contract (value ~70k) to investigate the electronic properties of initially produced delta-doped diamond layers; a further ~15k 3 month project has recently been added to this; this has led to monthly meetings between DMD and UCL staff E6 have been supplying UCL with world class delta doped diamond samples and have also been engaged in monthly meetings Both DMD and E6 have participated in the development of this proposal From this initial work one Applied Physics Letter paper has been published and a full Journal of Applied Physics paper is under consideration The collaboration has been publicised in various magazines and web sites, including 'Electronics Weekly (front page)' If funded the very collaborative activity will develop a web site; Element Six, DMD and UCL will all act to actively publicise the activity via press releases and similar A mid-point project workshop open to all will be arranged Collaboration Dr Richard Lang, of DMD Ltd, will take over all responsibility for the collaboration and hold all partner meetings at 3 monthly intervals to ensure that this process is effective. Dr Richard Balmer, of Element Six, will be in charge of all growth aspects of the collaboration, whilst Professor Richard Jackman will manage UCL activities. The three named have already shown highly effective communication and collaboration skills, and are used to regular (almost daily) e-mail exchanges and phone calls. Arrangements for IPR issues between DMD, E6 and UCL are already in place. The value to the project of the DMD/E6 activity has been estimated as 205K GBP. Exploitation and application DMD and E6 have every desire t exploit the outcomes of the proposed activity, and DMD as an SME is well placed to take the pre-competitive research outcomes and develop them into the inputs required for R&T development for product prototyping. Arrangements are already in place for UCL to exploit activities with DMD and E6. Patents will be pursued where appropriate. Capability This close collaboration will bring the extensive business experience of Dr Richard Lang (of DMD, but formally a senior manage with Filtronic Ltd) to bear on creating 'impact' from the proposed activity. Professor Jackman has previously licensed diamond device technology to UK industry, earning UCL in excess of 150k, so can also be considered active with regard to exploitation and achievement of maximum impact.

Publications

10 25 50
 
Description A new way of making diamond useful for high performance electronics, called delta doping, has been developed.
Exploitation Route Start up company Diamond Microwave Devices Ltd

Recently started EU Horizon 2020 project on high performance transistors known as 'GREENDIAMOND', 11 partners from 5 countries, €4M 4-year programme.

New collaboration initiated with St Petersburg university on delta-doped diamond structures - one publication to date - 2 more pending
Sectors Aerospace, Defence and Marine,Energy,Environment

 
Description Findings have lead to start up company, Diamond Microwave Devices Ltd Findings contributed to the award of a Horizon 2020 project on Diamond Transistors (GREENDIAMOND), 11 partners, 5 countries, including myself. 2015-2019. New collaboration initiated with St Petersburg university on delta-doped diamond structures - one publication to date - 2 more pending.
First Year Of Impact 2011
Sector Aerospace, Defence and Marine,Electronics,Energy
Impact Types Cultural,Economic

 
Description BAE Systems plc EPSRC CASE Award competition
Amount £24,500 (GBP)
Organisation BAE Systems 
Department BAE Systems Submarine Solutions
Sector Private
Country United Kingdom
Start 09/2014 
End 03/2018
 
Description BAE Systems plc EPSRC CASE Award competition
Amount £69,500 (GBP)
Funding ID EPSRC Voucher number 14220025 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2014 
End 03/2018
 
Description Direct Industrial funding (Applied Nanostructured Solutions Inc)
Amount $611,526 (USD)
Organisation Applied Nanostructured Solutions 
Sector Private
Country United States
Start 02/2013 
End 01/2016
 
Description Direct Industrial funding (Applied Scintillation Technologies Ltd)
Amount £103,148 (GBP)
Organisation Applied Scintillation Technologies 
Sector Private
Country United Kingdom
Start 09/2011 
End 03/2015
 
Description Direct Industrial funding (Photonis SAS)
Amount £74,000 (GBP)
Organisation Photonis SAS 
Sector Private
Country France
Start 01/2011 
End 12/2014
 
Description Horizon 2020
Amount € 4,000,000 (EUR)
Funding ID GREENDIAMOND 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 05/2015 
End 05/2019
 
Description KTN (Electronics, Photonics and Sensors) EPSRC CASE Award competition
Amount £25,000 (GBP)
Organisation Diamond Microwave Devices 
Sector Private
Country United Kingdom
Start 09/2012 
End 03/2016
 
Description KTN (Electronics, Photonics and Sensors) EPSRC CASE Award competition
Amount £69,121 (GBP)
Funding ID EPSRC Voucher number 11330191 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 09/2012 
End 03/2016
 
Description Q-NEURO: Diamond Quantum Technology for the Investigation of Neurological disease
Amount £282,470 (GBP)
Funding ID EP/R034699/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 07/2020
 
Description BAES diamond devices 
Organisation BAE Systems
Department BAE Systems Submarine Solutions
Country United Kingdom 
Sector Private 
PI Contribution The design and fabrication of diamond devices for submarine applications
Collaborator Contribution Identification of submarine needs; device packaging; in-house test facilities; diamond substrates
Impact Diamond devices designed and fabricated by the PIs team are being fitted on HMS Artful, the UKs third nuclear ASTUTE class submarine for safety critical operation
Start Year 2010
 
Description CEA - Atomic Energy Commission 
Organisation Alternative Energies and Atomic Energy Commission (CEA)
Country France 
Sector Public 
Start Year 2005
 
Description Cambridge SemiConductor 
Organisation Cambridge Semiconductor Limited
Country United Kingdom 
Sector Private 
Start Year 2005
 
Description DMD diamond transistors 
Organisation Diamond Microwave Devices
Country United Kingdom 
Sector Private 
PI Contribution Design and evaluation of diamond transistors and diamond materials
Collaborator Contribution RF device design know how; in-house test facilities; unique diamond materials; diamond substrates
Impact Several joint papers
Start Year 2010
 
Description Diamond-based multi-function sensors for extreme environments 
Organisation BAE Systems
Department BAE Systems Maritime – Naval Ships
Country United Kingdom 
Sector Private 
PI Contribution Design, research, development and prototyping
Collaborator Contribution Need, drive and test facilities
Impact Currently confidential
Start Year 2016
 
Description Element Six Ltd (UK) 
Organisation De Beers Group
Department Element Six
Country Luxembourg 
Sector Private 
Start Year 2005
 
Description Lockheed Martin work 
Organisation Lockheed Martin
Country United States 
Sector Private 
PI Contribution Materials science; device design; device fabrication; device test
Collaborator Contribution Access to unique nanostructured materials
Impact Joint publications
Start Year 2013
 
Description Photonis diamond devices 
Organisation Photonis SAS
Country France 
Sector Private 
PI Contribution Deign work; materials science; device fabrication; diamond growth
Collaborator Contribution Design work; in-house test facilities; diamond materials and substrates
Impact One PhD thesis; two publications; 4 patents
Start Year 2011
 
Title A PHOTO CATHODE FOR USE IN A VACUUM TUBE AS WELL AS SUCH A VACUUM TUBE 
Description The invention relates to a photo cathode for use in a vacuum tube at least comprising a cathode layer, having an entrance face capable for absorbing photons impinging on said cathode layer, and an exit face for releasing electrons upon impinging of said photons; as well as an electron exit layer, in facing relationship with said exit face of said cathode layer for improving said releasing of said electrons; and a carbon containing layer, positioned between said exit face of said cathode layer and said electron exit layer, for bonding said electron exit layer to said cathode layer. The invention also relates to a vacuum tube using such a photo cathode. 
IP Reference WO2011112086 
Protection Patent granted
Year Protection Granted 2011
Licensed Commercial In Confidence
Impact commercial development of a diamond based night vision device
 
Title AN ELECTRON MULTIPLYING STRUCTURE FOR USE IN A VACUUM TUBE USING ELECTRON MULTIPLYING AS WELL AS A VACUUM TUBE USING ELECTRON MULTIPLYING PROVIDED WITH SUCH AN ELECTRON MULTIPLYING STRUCTURE 
Description The invention relates to an electron multiplying structure for use in a vacuum tube using electron multiplying and to an vacuum tube using electron multiplying provided with such an electron multiplying structure. According to the invention an electron multiplying structure is proposed for use in a vacuum tube using electron multiplying, the electron multiplying structure comprising an input face intended to be oriented in a facing relationship with an entrance window of the vacuum tube, an output face intended to be oriented in a facing relationship with a detection surface of the vacuum tube, wherein the electron multiplying structure at least is composed of a semi-conductor material layer adjacent the detection windows. 
IP Reference WO2011149351 
Protection Patent granted
Year Protection Granted 2011
Licensed Commercial In Confidence
Impact Commercial development of diamond-based electron amplifiers
 
Title DIAMOND-BASED SENSOR DEVICE FOR USE IN HOSTILE ENVIRONMENTS 
Description A sensor device is provided to sample data from a fluid in a sealed environment. The sensor comprises a housing and a diamond within the housing. The housing is formed such that the device is reversibly insertable into the sealed environment so that the diamond directly interfaces with the sealed environment. 
IP Reference US2019064099 
Protection Patent application published
Year Protection Granted 2019
Licensed Yes
Impact UCL spin out company
 
Title ELECTRON MULTIPLIER DETECTOR FORMED FROM A HIGHLY DOPED NANODIAMOND LAYER 
Description The invention relates to a system for detecting electromagnetic radiation or an ion flow, comprising an input device (10) for receiving the electronic radiation or the ion flow and emitting so-called primary electrons in response, a multiplier (20) of electrons in transmission, for receiving the primary electrons and emitting so-called secondary electrons in response, and an output device (30) for receiving the secondary electrons and emitting an output signal in response. Said electron multiplier (20) comprises at least one nanocrystalline diamond layer (21) doped with boron in a concentration of higher than 5.1019cm~3. 
IP Reference WO2011157810 
Protection Patent granted
Year Protection Granted 2011
Licensed Commercial In Confidence
Impact Commercial development of a diamond-based electron multiplier
 
Title ELECTRON MULTIPLIER DEVICE HAVING A NANODIAMOND LAYER 
Description The invention relates to an electron multiplier (1) for a system for detecting electromagnetic radiation or an ion flow. The multiplier (1) comprises at least one active structure (2) for receiving a flow of incident electrons and for emitting a flow of so-called secondary electrons in response. Said active structure (2) comprises a substrate (3) on which a thin nanodiamond layer (4) is arranged, wherein said layer consists of diamond particles, the average size of which is no greater than 100 nm. 
IP Reference WO2012034948 
Protection Patent granted
Year Protection Granted 2012
Licensed Commercial In Confidence
Impact Commercial development of a diamond based electron multiplier device
 
Company Name Corite Technology Ltd 
Description A spin-out from the PIs research team with 4 of the PIs team members to exploit diamond sensor technology 
Year Established 2017 
Impact Start up