Deep level transient spectroscopy study for the development of ion-implanted silicon field-effect transistors for spin-dependent transport

A deep level transient spectroscopy (DLTS) study of defects created by low-fluence, low-energy ion implantation for development of ion-implanted silicon field-effect transistors for spin-dependent transport experiments is presented. Standard annealing strategies are considered to activate the implanted dopants and repair the implantation damage in test metal-oxide-semiconductor (MOS) capacitors. Fixed oxide charge, interface trapped charge and the role of minority carriers in DLTS are investigated. A furnace anneal at 950 $\rm ^{o}$C was found to activate the dopants but did not repair the implantation damage as efficiently as a 1000 $\rm ^{o}$C rapid thermal anneal. No evidence of bulk traps was observed after either of these anneals. The ion- implanted spin-dependent transport device is shown to have expected characteristics using the processing strategy determined in this study.Comment: 4 pages, 6 figure

Charge-based silicon quantum computer architectures using controlled single-ion implantation

We report a nanofabrication, control and measurement scheme for charge-based silicon quantum computing which utilises a new technique of controlled single ion implantation. Each qubit consists of two phosphorus dopant atoms ~50 nm apart, one of which is singly ionized. The lowest two energy states of the remaining electron form the logical states. Surface electrodes control the qubit using voltage pulses and dual single electron transistors operating near the quantum limit provide fast readout with spurious signal rejection. A low energy (keV) ion beam is used to implant the phosphorus atoms in high-purity Si. Single atom control during the implantation is achieved by monitoring on-chip detector electrodes, integrated within the device structure, while positional accuracy is provided by a nanomachined resist mask. We describe a construction process for implanted single atom and atom cluster devices with all components registered to better than 20 nm, together with electrical characterisation of the readout circuitry. We also discuss universal one- and two-qubit gate operations for this architecture, providing a possible path towards quantum computing in silicon.Comment: 9 pages, 5 figure

Party rules, party resources, and the politics of parliamentary democracies: how parties organize in the 21st Century

This article introduces the first findings of the Political Party Database (PPDB) project, a major survey of party organizations in parliamentary and semi-presidential democracies. The project’s first round of data covers 122 parties in 19 countries. In this paper we describe the scope of the database, then investigate what it tells us about contemporary party organization in these countries, focussing on parties’ resources, structures and internal decision-making. We examine organizational patterns by country and party family, and where possible we make temporal comparisons with older datasets. Our analyses suggest a remarkable coexistence of uniformity and diversity. In terms of the major organizational resources on which parties can draw, such as members, staff and finance, the new evidence largely confirms the continuation of trends identified in previous research: i.e., declining membership, but enhanced financial resources and more paid staff. We also find remarkable uniformity regarding the core architecture of party organizations. At the same time, however, we find substantial variation between countries and party families in terms of their internal processes, with particular regard to how internally democratic they are, and in the forms that this democratization takes

Ion beam induced charge and numerical modeling study of novel detector devices for single ion implantation

C1 - Journal Articles Referee

Controlled shallow single-ion implantation in silicon using an active substrate for sub-20-keV ions

C1 - Journal Articles Referee

Not as bad as we feared or even worse than we imagined? Assessing and explaining conservative members’ views on coalition

Although often treated as such, political parties are not unitary actors. Presumably, therefore, their leaders have to take at least some account of the views of their followers – not least when deciding whether or not to enter a coalition with other parties. Hitherto there has been relatively little research into those views. This article uses a survey of members of the UK’s Conservative Party in order to elicit and explain their thinking on the coalition the party formed with the Liberal Democrats in 2010, on the performance of the government since then, and on the prospects of a similar arrangement after the next general election. It finds that, although they largely approve of the government’s record, grassroots Tories regret the decision to go into coalition in the first place. However, they would sanction a continuation of the arrangement as the price of hanging onto power after the next election. Different members, of course, have different views, and these are best explained by ideological rather than demographic variables, as well as by members’ views on their party leader and – at least in part – their levels of activism