Nanowire transistors for applications in high-performance, low-power, and low-noise electronics

Seongmin Kim, Purdue University

Abstract

Low-dimensional materials have gained great interest as promising candidates for integrating high performance logic devices and thin film transistors to sustain the progress in CMOS scaling and enable transparent and/or flexible electronics. In order to use nanowire transistors for commercial electronics, however, several challenges remain to be solved. It is necessary to integrate transistors with stable device characteristics and low noise. Due to the large surface-to-volume ratio of the nanowires, electrical characteristics of the nanowire transistors are strongly affected by the surface states which impact key device performance metrics. Hence, understanding the role of the interface at the nanowire channel and the contact in the current saturation, threshold voltage, and mobility, is important for optimizing device performance and projecting scaling with channel length. This thesis focuses on solving such issues to fabricate nanowire transistors that are suitable for low-power, high-performance, and/or low-noise logic and display/memory circuitry which could also be applied to transparent electronics. This study investigated the effects of the nanowire interfaces on the currentvoltage relation using (i) 1/f noise measurement, (ii) numerical device simulation, and (iii) current-voltage measurement. The role of contacts on the device performance is analyzed accompanied by a physical model in nano-devices. Interface optimization techniques (oxygen plasma, laser annealing, ozone treatment, molecular passivation) compatible with low temperature process were developed. Based on the understanding of interface mechanisms and the development approaches to optimize the device performance, high-performance, low power, low-noise transparent transistors were fabricated that could be applied to transparent logic and display circuitry.

Degree

Ph.D.

Advisors

Janes, Purdue University.

Subject Area

Electrical engineering|Nanoscience|Nanotechnology

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