Electrical and Electro-Optical Characterization of Ultra-Wide Band Gap Semiconductors Devices

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Journal Title

Journal ISSN

Volume Title

Perustieteiden korkeakoulu | Master's thesis

Date

2021-08-24

Department

Major/Subject

Advanced Materials for Innovation and Sustainability

Mcode

SCI3083

Degree programme

Master’s Programme in Advanced Materials for Innovation and Sustainability

Language

en

Pages

72 + 2

Series

Abstract

Due to the increasing use of new energies and new ways of transportation, the electric grid requires novel power devices that allow energy to be saved. Among semiconductors, diamond is one of the promising materials that is well known to overpass the current silicon semiconductor due to its physical properties better suited for high power application. This paper aims to study and understand the electrically active defects present in recent diamond power devices, such as Schottky diodes or Metal Semiconductor Field Effect Transistors (MESFET). These defects can be created during the manufacturing steps and impact the electrical performances of the component. To characterize the potential defects present in the device, we mainly used two methods: Thermal Admittance Spectroscopy (TAS) and Deep Level Transient Spectroscopy (DLTS). Two components were studied by using the previous methods and other simple electrical measurements, a Schottky diode and a MESFET. Regarding the diode, the results showed no defects except boron with an activation energy of 0.34 eV and a capture cross section of 7×10-12 cm-2 determined by TAS. Concerning the transistor, DLTS and current-voltage measurements revealed a potential activation by light or thermal energy of the pn-junction between the channel and the 1b diamond substrate. Further investigations on the junction also indicated the presence of a conductive layer situated on the side of the sample, that could have affected the previous experiments. These results suggest that well-designed diamond components can contain only a few defects similarly to the diode. The results also demonstrate that the substrate-channel pn-junction or diamond growth on the side of the component can impact its functioning and should be considered when designing the device.

Description

Supervisor

Slotte, Jonatan

Thesis advisor

Ferrandis, Philippe

Keywords

diamond, Schottky diode, MESFET, DLTS, admittance spectroscopy, defects

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