Characterization of Si nanocrystals using mist deposition

Open Access
- Author:
- Sridhara, Karthik
- Graduate Program:
- Electrical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- November 20, 2003
- Committee Members:
- Jerzy Ruzyllo, Thesis Advisor/Co-Advisor
Jerzy Ruzyllo, Thesis Advisor/Co-Advisor
Suman Datta, Thesis Advisor/Co-Advisor - Keywords:
- Silicon Quantum Dots
Mist Deposition
Silicon nanocrystals
MOS Capacitors - Abstract:
- In this study, characterization of Metal Oxide Semiconductor (MOS) capacitor embedded with Silicon Quantum Dots (QDs) is done. This study aims to understand the oxidation dependent size variation of Si QDs. Ion implantation being the choice of deposition for Si nanocrystal experiments, a different technique: Mist Deposition is chosen as a vehicle of deposition for this study. Deposition of times of 20 mins and 10 mins with a density of .1mg/ml is chosen with the QDs suspended in toluene. Colloidal Si QD solution is prepared which is then mist deposited onto an n-type silicon substrate. The substrate, along with the QDs, is thermally oxidized at 800°C for a pre-calculated time: 5 min (2.14 nm), 30 min (4.63 nm) and 90 min (8.34 nm). Metal (Aluminum) contacts are deposited on the samples thus forming MOS capacitors—embedded with Si QDs. Primary method of characterization is electrical characterization. Electrical characterization involving Current-Voltage (I-V) and Capacitance-Voltage (C-V) measurements are employed to understand the role by QDs in altering the MOS capacitor behavior. With varying oxide thickness, the characterization results obtained are analyzed to understand the oxidation dependent size variation of the oxidized Si QDs. The oxide thickness is varied to also study the role of oxide in assisting tunneling. C-V hysteresis is performed to memory effect or charge storage in the QDs. The results obtained confirm the QD size dependent variation of electrical characteristics of MOS capacitors. I-V measurements confirm QDs playing a role while the C-V measurements indicating the existence of tunneling current. Hysteresis measurements strongly indicate charge storage in the QDs while being absent in the control samples (without QDs).