Request Expert

Expert has over thirty years experience in the design, micro-fabrication, analysis and modeling of electronic devices, transistors, and sensor arrays. He has extensive experience with the advanced processes for device fabrication: depositing the metal electrode and contact layers by sputtering, by electron-beam or by thermal evaporation; the deposition of the insulator layers by plasma-enhanced chemical vapour deposition (PECVD), reactive sputtering and atomic layer deposition (ALD); and the formation of ultrathin oxides and oxynitrides of Al, Hf, Zr and Gd by PECVD on silicon or III-V semiconductors.

In the last 10 years he has developed considerable expertise with the deposition of gate-quality insulator films on semiconductors using conventional thermal ALD and plasma-enhanced ALD (PE-ALD). This includes specific experience with the precursor TMA (trimethyl aluminium) for the formation of aluminium oxide and alkylamide precursors for the formation of Hf and Ti oxides. The Hf and Ti nitrides and oxynitrides have been formed using ammonia plasma in the reaction pulses.

Expert has extensive experience with the instrumentation and techniques required to determine the current - voltage (IV), capacitance – voltage (CV), and impedance characteristics of electronic devices using a wide range of instruments; pico-ammeters with DC voltage sources, source-measure units, and precision LCR meters (HP 4284A and 4275A covering the frequency range from 20 Hz-10 MHz). He is familiar with control of the instruments using codes written in Labview, Visual Basic, C++, Fortran, and HT Basic.

Expert is experienced with film analysis using fourier-transform infrared spectroscopy (FTIR), spectroscopic ellipsometry (SE), x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy; has monitored the growth of insulator films in-situ and characterized the films ex-situ using both SE and XPS; is experienced in analyzing films using angle-resolved Auger electron spectroscopy (AES) and obtained composition profiles from sputter depth-profiling of the secondary-ion mass spectra or XPS signals. He has worked with other scientists evaluating materials by Rutherford backscattering spectrometry, medium-energy ion scattering, nuclear reaction analysis, transmission electron microscopy (TEM and STEM).

Expert is familiar with the etching processes (wet, reactive-ion, and inductively-coupled plasma) and the lithography used to pattern the layers. In fact his work has touched on most processes used to fabricate advanced deep-submicron devices including their bonding, encapsulation, planarization, chemical-mechanical polishing, and the design of masks for the lithography and printing processes using software such as AutoCAD or L-edit.


In the past 10 years Expert’s work has focused on fabricating sensor arrays that could detect specific oligonucleotides and proteins in electrolyte solutions. These arrays (with 49 elements) could indicate the existence of pathogens in real solutions obtained in the field. The sensor arrays used commercial metal-oxide-silicon (MOS) field effect transistors (MOSFETs) as the sensing elements and analogue and digital complementary MOS (CMOS) circuits to process the sensor signals. To demonstrate that different target molecules from test solutions could be detected in the individual sensors in an array, the FET surfaces were functionalized (spotted) with molecules that would conjugate with the various target molecules; i.e., the array elements were spotted with oligonucleotides (DNA fragments) that were complementary to the target and control molecules. The test and control solutions flowed over the sensor elements on the surface through a microfluidic channel fabricated in an elastic polymer applicator pressed against the sensor array surface. Similar technology could be used to create sensors arrays that use amperometric measurements rather than changes in current from field–effect sensors.

Expert has collaborated extensively to develop simulation software to predict the performance of the switching and sensing elements using two-dimensional finite element and finite difference calculations. These use the standard equations for the semiconductor and gate insulator and the the layers of linkers and biomoleules are described as permeable membranes. Each layer is described by the appropriate Poisson-Boltzmann equation, stoichiometric relationships, and the necessary boundary conditions.

Expert is focussed on the global effort that has shown that single wall carbon nanotubes (CNTs) could be fabricated into ambipolar MOS devices with oxide insulator layers composed of Hf and Al oxides produced by ALD. By optimization of the source, drain and gate contacts, stable complementary p- and n-type CNTs will be integrated to form a form of carbon-based CMOS technology that used CNT transistors but would have lower costs per unit area. The transistors could have bandgaps close to that of silicon and channel lengths on the order of microns, but with considerably higher carrier mobility, switching speeds, and frequency response than conventional Si CMOS transistors having comparable dimensions.

Expert hopes to show that biomedical sensors can be fabricated by functionalizing CNT networks produced by printing processes (using inks containing CNTs for ink-jet, gravure, or screen printing). These processes can be used to make Ag or graphitic (multilayer graphene) source/drain contacts. Since the ALD printing technology is advancing rapidly to the point where roll-to-roll or large batch processing is feasible, this could dramatically reduce the cost of the sensor arrays by using printing processes on rolls or sheets of flexible plastic substrates (“printable electronics”).


While working at NRC Canada Expert developed a process for Nortel Networks to produce a-Si/SiO2 anti-reflection coating stacks for waveguide lasers using an electron-cyclotron resonance chemical-vapour deposition process (1999).
He was a consultant to Fiber Optic Gateways in Fredericton, NB, to produce oxides and nitrides for optical waveguide devices (2000). He was co-ordinator of a subcontract to make RF MEMS switches from COM DEV Cambridge, Ontario under a contract with the Canadian Space Agency (2001).
He was advisor to ALFT of Hull, Quebec on applications for their high-power pulsed plasma x-ray source (2001-2005).
He evaluated metallo-organics provided by Epichem, Inc. in the U.K. as part of a collaboration to find new precursors for the chemical vapour and atomic layer deposition processes for rare-earth oxides and silicates (2001-2005).