氮化鎵金-氧-半二極體之電性及材料分析與利用分子束磊晶成長矽化三鐵於發光二極體之研究

Electrical Property and Material Analysis of GaN MOS Diode and Investigation of Fe3Si Deposited on LED by Molecular Beam Epitaxy

邱淵楠(Yuen-Nan Chiu)

指導教授 ： 郭瑞年 ； 洪銘輝

國立清華大學/理學院/物理學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00458

摘要

part1:
現今高科技產業蓬勃發展，對於高速元件需求逐日漸增，化合物半導體對於發光二極體(LED)和半導體雷射(LASER)，及高功率電子元件 如:高電子遷移率電晶體(HEMT),金氧半場效電晶體(MOSFET)…等等，扮演極為重要角色。我們著重於氮化鎵金屬氧化物半導體的相關研究，利用超高真空分子束磊晶技術(UHV-MBE)成長氧化鎵釓於氮化鎵上，並利用X光反射率(X-ray reflectivity)、高解析度穿透式電子顯微鏡(High-resolution transmission electron microscopy)可得知介面十分陡峭,粗糙度極小.利用電容-電壓(C-V)，電流-電壓(I-V)曲線得知氧化鎵釓介電常數κ約達(15),電場於1MV/cm時漏電流約10-8A/cm2及使用Terman method 去推算介面態密度(Dit)約1012cm-2eV-1， 另一方面利用原子層沈積法(ALD)成長二氧化鉿於氮化鎵上，並利用X光反射率(X-ray reflectivity)、高解析度穿透式電子顯微鏡(High-resolution transmission electron microscopy)可得知介面粗糙度達4埃，由C-V，I-V曲線得知二氧化鉿介電常數κ約達15，介面態密度 (Dit) 大約1012cm-2eV-1，電場於1MV/cm時漏電流約10-8A/cm2。利用二氧化鉿，氧化鎵釓當閘極氧化層有完好的電性曲線，對於未來的氮化鎵空乏型金氧半場效電晶體(D-mode MOSFET)，增強型金氧半場效電晶體(E-mode MOSFET)或甚至金氧半高電子遷移率電晶體(MOS-HEMT)都具極大貢獻。
part2:
自旋的電子或自旋電子乃屬於一門運用自旋自由度於電子元件內的初期研究領域自旋發光二極體內的場致偏極光對於載子自旋注入於非磁性半導體內效率特性方面的表現極為重要.我們利用光學的儀器區分出左旋偏振光及右旋偏振光並求出其相對自旋偏極量.現今具有高結晶性且高介面品質的矽化三鐵已藉由真空度低於10-10 torr的分子束磊晶系統成功的成長於砷化鎵上.矽化三鐵被視為一種在費米階上百分之百極化方向的半金屬材料,使得矽化三鐵可成為具吸引力的高電子注入性材料.自旋電子經由矽化三鐵經由蕭基能障到砷化鎵的電子注入率已被量測.自旋偏極率於室溫及外加磁場0.1特司拉的情況下大約為零.為了去提高其偏極量我們必須將有覆蓋矽化三鐵的發光二極體置於低溫及高磁場下相對低去降低擾動效應及增加再磁化現象.

關鍵字

氮化鎵 ； 分子束磊晶 ； 矽化三鐵 ； 發光二極體 ； 自旋電子學 ； X-光光電子能譜

並列摘要

part1:
With the development of technological industry in recent twenty years, the demand for high- speed device get more day by day. Compound semiconductors which are such as Light Emission Diode (LED), and high power electronic device for example: High-Electron Mobility Transistor (HEMT), Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) played an important role. We focus on research about GaN MOS diode and fabricate (Ga2O3)Gd2O3/GaN by using ultra high vacuum molecular beam epitaxy (UHV-MBE).We take advantage of X-ray reflectivity (XRR) and High-resolution transmission electron microscopy (TEM) to make sure that interface was abrupt and had less roughness. Using capacitance-voltage(C-V), current-voltage(I-V) curve to understand that (Ga2O3)Gd2O3 dielectric constant κ was almost 15, interfacial state(Dit) around 1012cm-2eV-1 by using Terman method and leakage current around 10-8A/cm2 at 1MV/cm.On the other hand, we make use of atom layer deposition(ALD) to grow HfO2 on GaN ,and take X-ray reflectivity (XRR) and High-resolution transmission electron microscopy (TEM) to realize that surface roughness was roughly 0.4nm.From C-V curve, we know that dielectric constant κ value was almost 15, interfacial state (Dit) around 1012cm-2eV-1 and leakage current was around 10-8A/cm2 at 1MV/cm.We found (Ga2O3)Gd2O3 and HfO2 unpin the GaN Fermi level so that they have great contribution for depletion-mode and enhancement-mode GaN MOSFET and MOS-HEMT.
part2:
Spin electronics, or spintronics, is a nascent field of research whereby the spin degree of freedom in electronic devices is exercised. The electroluminescence (EL) polarization of the spin light emission diode (spin-LED) is important in the characterization of spin injection efficiency into non-magnetic semiconductor. We use optical instruments to distinguish the left and right circular polarized light and find out its relative spin polarization. The Fe3Si/GaAs(001) hybrid structure with high crystalline and interfacial quality have been fabricated in my group by using ultra-high vaccum molecular-beam epitaxy system(UHV-MBE) with base pressure under 10-10 torr. The Fe3Si is regarded as half metal with 100﹪spin polarized at the Fermi level, hence making Fe3Si an attractive material for electric spin injection. Spin injection into GaAs from Fe3Si, spin aligning contact, via a Schottky barrier was measured. The spin polarization was roughly zero at room temperature and externally magnetic field of 0.1 tesla. In order to increase the polarization scales, we will measure the LED with Fe3Si in low temperature and highly externally magnetic field to decrease thermal disturbance and increase demagnetization respectively in the future.

並列關鍵字

GaN ； MBE ； Fe3Si ； LED ； Spintronics ； XPS

參考文獻

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4. GaN Metal-Semiconductor Field-Effect Transistor Project Ⅱ, EECS521 Profect Ⅱ.MAR.2003 Jaeyoung Kang.

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7. Materials Research Bulletin, March 2002 issue, on” Alternative Gate Dielectric for Microelectronics”, Ed. by R.M. Wallace and G. D. Wilk.