Tác giả: Thi Trần Anh Tuấn. Professor Dong-Hau Kuo (người hướng dẫn)

National Taiwan University of Science and Technology. Năm: 2015.

Mô tả: 166Tr. Kích thước: 30cm.

Abstract:

High thermal conductivity, high electron mobility, high electron saturation velocity, and large band gap of nitride based materials have attracted many research interests in recent years. The GaN and InGaN materials have brought promising future for the application of electronic devices such as metal–oxide–semiconductor field effect transistors (MOSFETs), hetero junction field-effect transistors (HJ-FETs), Schottky diodes, p–n junction diodes, laser diodes, light emitting diodes (LEDs) etc. However, high-quality GaN, InGaN films and III-V nitride semiconductors for optoelectronic and electronic devices often have been grown on sapphire and several other semiconductor substrates by using metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) above 800^oC. The developments of III-V nitride materials and their devices made by using low-cost methods at low processing temperatures are very important in fabricating electronic devices.

In this study, all diodes based on GaN and InGaN materials will be made at the low temperature with the cost-effective and reactive radio-frequency (RF) sputtering technique. The GaN and its alloy films were characterized by FE-SEM, EDS, XRD, TEM, AFM and Hall measurement at the room temperature. The electrical characterizations of diodes were determined by I–V and C–V measurements. The characteristics of our diodes can be successfully explained with the thermionic-emission (TE) model. Cheungs' and Norde methods were used to determine all electrical parameters of Schottky and p–n junction diodes.

For the diode devices based on n–GaN and n–InGaN, the 500^oC-annealed n–GaN MS (metal–semiconductor) and MOS (metal–oxide–semiconductor) Schottky diodes showed the smallest leakage currents of 1.02x10^-8 and 1.86x10^-9 A, respectively, at -1V. The highest SBHs for n–GaN MS and MOS Schottky diodes were calculated to be 0.79 and 0.81 eV , respectively, by the Cheungs’ method, and 0.91 and 0.94 eV by the Norde method. The n–GaN MOS diode showed a high series resistance of 84.4 kΩ, as compared to 27.9 kΩ for the n–GaN MS diode. In addition, n–InGaN MS and MOS Schottky diodes were studied before and after annealing at 400^oC. The 400^oC-annealed samples displayed the leakage current of 3.86x10^-6 (MS) and 1.42x10^-7 A (MOS). The SBH of n–InGaN MOS diode increased from 0.69 eV (I–V), 0.77 eV (Norde) to 0.82 eV (C–V) after annealing at 400^oC. By C–V measurement for n–InGaN MOS diode, the carrier concentration was found to be 4.48x10¹⁷ cm^-3 for the as-deposited and 2.41x10¹⁷ cm^-3 for the annealed samples. The n–InGaN MOS diode had a small series resistance of 911 Ω, as compared to 84.4 kΩ for the n–GaN MOS diode.

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