Restriction lift date: 2021-12-15
Monolayer doping of bulk and thin body group IV semiconductors
University College Cork
The turn of the new year from 2019-2020 has brought us into a new decade with an unforeseen worldwide halt to what was previously considered “normal” life, due to a virus (coronavirus-19) with dimensions measured by scanning electron microscopy (SEM) to be in the nanometre range. This has emphasized the importance for the general public of acknowledging particles and materials in this nanometre range which cannot be seen without electron microscopy. Some of the technology being used to fight these viruses, such as ventilators, operate using electronics which contain semiconductor materials. Since the mid 1900 s the size of these electronics has decreased while doubling their quantity of transistors in line with Moore’s law. This has allowed for increased performance with lower power consumption. Scaling of metal-oxide-semiconductor field effect transistors (MOSFETs) has progressed from the original micrometre range to current sub-10 nm dimensions, while also moving from planar to 3-dimensional (3-D) architectures. However, increasing difficulty has been found with these new and reduced material dimensions. All fabrication processes are stressed, but doping has particularly found limitations in this region. High concentrations of dopant atoms are required at increasingly shallow depths, while maintaining the crystalline integrity of the planar or 3-D doped substrate. Traditional methods of introducing these dopant atoms, such as ion implantation, have found difficulty with damage production and conformality on state-of-the-art applications. Monolayer doping, which is a method of semiconductor doping through chemical functionalisation of the target substrate with the required dopant-containing molecules, has shown promise as an alternative method for this state-of-the-art doping.The aim of this thesis is to study the potential of monolayer doping for application to materials used in current and future transistor devices.
MLD , ECV , Conformal , Nanowires , Arsenic , Phosphorus
Kennedy, M. N. 2020. Monolayer doping of bulk and thin body group IV semiconductors. PhD Thesis, University College Cork.