Date of Completion

5-4-2017

Embargo Period

10-31-2017

Keywords

quantum dot, silicon-on-insulator, gate dielectric, electron mobility, nonvolatile memory, floating gate, crystalline silicon, high-k insulator, threshold voltage

Major Advisor

Faquir Jain

Associate Advisor

John Chandy

Associate Advisor

Fotios Papadimitrakopoulos

Associate Advisor

John Ayers

Associate Advisor

Lei Wang

Field of Study

Electrical Engineering

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Quantum dot channel (QDC) and Quantum dot gate (QDG) field effect transistors (FETs) have been fabricated on crystalline Si and poly Si thin films using cladded Si and Ge quantum dots. In particular, this thesis presents modeling and fabrication of quantum dot channel field effect transistors (QDC-FETs) using cladded Ge quantum dots on poly-Si thin films grown on silicon-on-insulator (SOI) substrates. HfAlO2 high-k dielectric layers are used for the gate dielectric. QDC-FETs exhibit multi-state I-V characteristics which enable 2-bit processing, and reduce FET count and power dissipation, and are expected to make a significant impact on the digital circuit design. Germanium quantum dot QDC-FETs provide higher electron mobility than conventional polysilicon FETs, which is comparable to crystalline silicon.

Quantum dot channel FETs are also configured as floating gate quantum dot nonvolatile memories (QDC-QDNVMs). In NVMs, we use floating gate comprising of GeOx-Ge quantum dots. QD nonvolatile memories (QD-NVMs) are fabricated on crystalline silicon substrates. HfAlO2 high-k insulator layers are used for both tunnel gate oxide as well as control gate dielectric. QDC-NVMs not only provide significantly higher drain current ID, but also higher threshold voltage shifts (DVTH), and exhibit potential for fabricating multi-bit nonvolatile memories.

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