High performance hydrogen-terminated diamond field effect transistors

Russell, Stephen A.O. (2013) High performance hydrogen-terminated diamond field effect transistors. PhD thesis, University of Glasgow.

Abstract

Diamond provides extreme properties which make it suitable as a new substrate material for high performance electronics. It has the potential to provide both high frequency and high power performance while operating in extreme environments such as elevated temperature or exposed to corrosive chemicals or radiation. Research to date has shown the potential of diamond for this purpose with hydrogen-terminated diamond surface channel transistors already showing promise in terms of high frequency operation. The inherent instability of using atmospheric molecules to induce a p-type doping at this hydrogen-terminated diamond surface has so far limited power performance and robustness of operation.

This work reports upon the scaling of surface channel hydrogen-terminated transistors with FET gate lengths of 250 nm and 120 nm showing performance comparable to other devices published to date. The gate length was then scaled for the first time to sub-100 nm dimensions with a 50 nm gate length FET fabricated giving record high-frequency performance with a fT of 53 GHz. An adapted fabrication procedure was developed for this project with special attention paid to the volatility of the particles upon the diamond surface. Equivalent RF circuit models were extracted for each gate length and analysed in detail.

Work was then undertaken to investigate a more stable alternative to the atmospheric induced doping effect with alternative electron accepting materials being deposited upon the hydrogen-terminated diamond surface. The as yet untested organic material F16CuPc was deposited on to hydrogen-terminated diamond and demonstrated its ability to encapsulate and preserve the atmospheric induced sub-surface conductivity at room temperature.

For the first time an inorganic material was also investigated as a potential encapsulation for the hydrogen-terminated diamond surface, MoO3 was chosen due to its high electron affinity and like F16CuPc also showed the ability to preserve and even slightly enhance the sub-surface conductivity. A second experiment was performed using photoelectron spectroscopy to analyse in-situ deposition of MoO3 which indicated this material has the ability to induce surface transfer doping by itself without the aid of atmospheric particles.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Two publications resulted from the results described in Chapter 6: • S. A. O. Russell, S. Sharabi, A. Tallaire and D. A. J. Moran, “Hydrogen-terminated diamond field effect transistors with cut-off frequency of 53 GHz,” IEEE Electron Device Letters vol. 33, pp. 1471-1473, 2012 • D. A. J. Moran, O. J. L. Fox, H. McLelland, S. Russell and P. May, “Scaling of hydrogen-terminated diamond FETs to sub-100-nm gate dimensions,” IEEE Electron Device Letters vol. 32, pp. 599-601, 2011
• Keywords: diamond, field effect transistors, surface transfer doping, RF electronics, semiconductor device physics
• Subjects: Q Science > QC Physics; T Technology > TA Engineering (General). Civil engineering (General); T Technology > TK Electrical engineering. Electronics Nuclear engineering
• Colleges/Schools: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Supervisor's Name: Moran, Dr. David A.J.
• Date of Award: 2013
• Embargo Date: 8 September 2016
• Depositing User: Dr Stephen A O Russell
• Unique ID: glathesis:2013-4569
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 13 Sep 2013 07:52
• Last Modified: 26 Mar 2018 10:53
• URI: https://theses.gla.ac.uk/id/eprint/4569