FABRICATION AND CHARACTERIZATION OF ACTIVE NANOSTRUCTURES

Three different nanostructure active devices have been designed, fabricated and characterized. Junctionless transistors based on highly-doped silicon nanowires fabricated using a bottom-up fabrication approach are first discussed. The fabrication avoids the ion implantation step since silicon nanowires are doped in-situ during growth. Germanium junctionless transistors fabricated with a top down approach starting from a germanium on insulator substrate and using a gate stack of high-k dielectrics and GeO2 are also presented. The levels and origin of low-frequency noise in junctionless transistor devices fabricated from silicon nanowires and also from GeOI devices are reported. Low-frequency noise is an indicator of the quality of the material, hence its characterization can reveal the quality and perhaps reliability of fabricated transistors. A novel method based on low-frequency noise measurement to envisage trap density in the semiconductor bandgap near the semiconductor/oxide interface of nanoscale silicon junctionless transistors (JLTs) is presented. Low-frequency noise characterization of JLTs biased in saturation is conducted at different gate biases. The noise spectrum indicates either a Lorentzian or 1/f. A simple analysis of the low-frequency noise data leads to the density of traps and their energy within the semiconductor bandgap. The level of noise in silicon JLT devices is lower than reported values on transistors fabricated using a top-down approach. This noise level can be significantly improved by improving the quality of dielectric and the channel interface.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics & Astronomy

Year

2016

Author dc:creator

• Opondo, Noah Felix Ochieng

Contributors dc:contributor

• SAEED MOHAMMADI
• CHEN YANG
• LUIS M KRUCZENSKI
• GABOR A CSATHY

• Field emitters
• Germanium on Insulator
• interface Trap density
• Junctioless transistors
• Low frequency noise
• nanowire

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/1395

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-2611