Room-Temperature Single Atom Silicon Quantum Electronics
Lead Research Organisation:
University College London
Department Name: London Centre for Nanotechnology
Abstract
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| Description | Linked grant with Imperial College: Room-Temperature Single Atom Single Quantum Electronics |
| Organisation | Imperial College London |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | The Room-Temperature Single Atom Single Quantum Electronics grant consists of two linked EPSRC grants: our one at UCL (EP/V027700/1) and our linked grant (EP/V030035/1), led by Dr Zahid Durrani at Imperial College. At UCL, we fabricate deterministic single atom devices made from arsenic and phosphorus dopants in silicon using scanning tunnelling microscopy in an ultra-high vacuum system. We will combine this technique with the cleanroom sample fabrication processes developed at Imperial to make room-temperature single electron transistors (SETs). |
| Collaborator Contribution | The Imperial College group has a long-standing, internationally leading position in the design, nanofabrication, and measurement of single-electron and quantum dot devices, particularly devices capable of room-temperature operation, with a view to practical, nanoelectronics applications. At present, single-atom quantum dot transistors (SA-QDTs) device variability due to randomness in the number and location of the donor atom QDs leads to variations in the device operating points. Three approaches will be investigated by Imperial to overcome this. (1) Exploit device doping and size to obtain a regime where either few or zero dopant atoms exist in the SA-QDT point-contact. In a point-contact with doping density 1018-1019/cm3 and highly nanoscale length ~10 - 5 nm, the number of dopant atoms within the point-contact is greatly limited. Here, either 1-2, or zero dopant atoms may lie along the point-contact length, implying that devices either form SA-QDTs or are 'off'. Working devices can be identified using current threshold identification. (2) Investigate thermal annealing to move dopant atoms in the point-contact region. Dopant clusters may form in the SiO2 or dopant 'pile-up' may occur at the Si-SiO2 interfaces. In a zero-cost collaboration with Technical University Ilmenau (TUIL), Imperial investigate single-dopant atom implantation by SPL. Here, a hollow-tip AFM developed at TUIL will be used investigate precise ion deposition on devices. The results here will contribute to further development of the SPL tool, generating additional project impact for SPL tool manufacturers e.g. NPL, NanoAnalytic, Swiss litho. 'Coulomb diamond' I-V characteristics will be measured at both RT, and cryogenic temperatures, to determine the promising approaches, and investigate device physics. This work compliments complimentary work performed at UCL, which is carried out deterministically with scanning tunnelling microscopy, and these technologies will be combined towards the end of the grant. |
| Impact | N/A |
| Start Year | 2021 |