Single-donor ionization energies in a nanoscale CMOS channel

Abstract

One consequence of the continued downward scaling of transistors is the reliance on only a few discrete atoms to dope the channel, and random fluctuations in the number of these dopants are already a major issue in the microelectronics industry. Although single dopant signatures have been observed at low temperatures, the impact on transistor performance of a single dopant atom at room temperature is not well understood. Here, we show that a single arsenic dopant atom dramatically affects the off-state room-temperature behaviour of a short-channel field-effect transistor fabricated with standard microelectronics processes. The ionization energy of the dopant is measured to be much larger than it is in bulk, due to its proximity to the buried oxide, and this explains the large current below threshold and large variability in ultra-scaled transistors. The results also suggest a path to incorporating quantum functionalities into silicon CMOS devices through manipulation of single donor orbitals.

Few electron limit of n-type metal oxide semiconductor single electron transistors

“…On the contrary for similar samples but without nitride spacers [8] -and therefore smaller effective channel length -the first electrons are on shallow donors in the body of the silicon and detected at gate voltage much below the threshold voltage at room temperature. [18,19] In that case there is no MOSSET effect in the accumulation channel.…”

Tuning the electron transport at single donors in zinc oxide with a scanning tunnelling microscope

“…In contrast to single atoms on metal surfaces, whose ground state is determined by the impuritysubstrate combination, transport experiments at different gate voltages can explore a wider parameter space. Signatures of single donors have been resolved and valuable information such as the electron-binding energy have been extracted [11][12][13][14] . Being a two-terminal device STM lacks a gate electrode for tuning the energy levels of nanostructures.…”

The laser at fifty

“…And as transistors shrank, the numbers of these implanted impurities dropped to hundreds per transistor or less, making the position of individual dopants matter 2,3 , and raising the prospect of 'engineering' individual defects into devices.…”