不同溫度及環境熱退火處理對於氧化鋅/氮化鎵異質接面發光二極體發光特性影響之研究

A Study on Annealing Temperature and Environment on the ZnO/ GaN Heterojunction Light Emitting Diodes

陳彥廷(Yan-Ting Chen)

指導教授 ： 劉代山

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2014年)

摘要

本研究利用射頻磁控共濺鍍系統，分別使用氧化鋅、氮化鋁靶材製作出未摻雜氧化鋅薄膜與摻雜的氮化鋁-氧化鋅共濺鍍薄膜，探討在不同溫度以及不同氣體環境熱處理之薄膜特性與光電特性，並將未摻雜氧化鋅薄膜與氮化鋁-氧化鋅共濺鍍薄膜沉積在p型氮化鎵磊晶層上製作出異質結構及雙異質結構，量測元件的電流-電壓特性與光激發螢光光譜圖。研究結果顯示，AlN-ZnO/ZnO雙異質結構在真空熱處理後能增強能帶邊緣放射並抑制氧缺陷，其元件電流-電壓量測觀察到隨著熱處理溫度升高接觸電阻越小，亦發現元件之串聯電阻和啟動電壓隨熱退火溫度上升而降低，此外，由於高溫導致p型氮化鎵的Ga原子外擴散形成Ga-O界面層缺陷，使得真空800度時的串聯電阻大幅增加，而將氧化鋅薄膜於700度不同環境(大氣、氮氣、氧氣、真空)熱退火處理進行研究，從光激發螢光譜圖以及霍爾量測可以發現，氮氣和真空環境熱退火能夠活化施體離子使濃度提升，而大氣和氧氣因為含有氧氣，因此會使薄膜的本質施體離子受到補償使濃度下降。從電激發光光譜量測中觀察到主要的兩個發光波段，分別為位於430 nm屬於氧化鋅和p型氮化鎵能帶複合發光，與較廣區域的長波段發光，並觀察不同熱退火條件下製備之元件在不同發光波段的強度變化，對於發光特性的影響。

關鍵字

射頻磁控共濺鍍 ； 氮化鋁 ； 氧化鋅 ； 雙異質結構 ； 發光二極體

並列摘要

In this research, the researcher applied radio-frequency magnetron cosputtering system, producing ZnO and AlN-ZnO cosputtered films by separately using ZnO、AlN targets to investigate the feature of thermal annealing treatment thin film characteristic and photoelectricin characteristic different temperature and different gas environment. In addition, added ZnO and AlN-ZnO cosputtered films sediment in p-GaN produce heterostructures and double heterojunction, measuring device current-voltage characteristic and photoluminescence spectra. The result showed that after heat treatment, AlN-ZnO/ZnO double heterojunction structure could strengthen NBE and decreased Vo. We had observed from device current-voltage measure that the higher temperature is ,the smaller the contact resistance will be. Also, we discovered that series resistance and turn-on voltage would reduced because of the rising temperature. However, in order to high temperature , Ga atom in p-GaN cause external diffusion to take shape into native Ga-O bonding, which made Series resistance of vacuum 800℃ increased dramatically and forced ZnO thin film heat treatment in different environments of 700℃ (Atmosphere, Nitrogen, Oxygen, Vacuum), we also knew from photoluminescence spectra and hall measure that thermal annealing in nitrogen and vacuum could activate donor ions and promoted the concentration; In the other hand, Atmosphere and Oxygen circumstances included Oxygen so that the concentration would drop since the nature of the film being compensated donor ions. The major two Luminescence bands we observed from Electroluminescence measurements respectively were located in 430nm belonged to ZnO, p-GaN band recombination, and wider section of long wavelength emission. Simultaneously, observing the influences of intense changes in different Luminescence bands when using differ thermal annealing condition.

並列關鍵字

RF cosputtering ； AlN ； ZnO ； double heterojunction ； light-emitting diode.

參考文獻

【1】 S. Nakamura, M. Senoh, N. Iwasa, and S. Nagahama, “High-Brightness InGaN Blue, Green and Yellow Light-Emitting Diodes with Quantum Well Structures ”, Jpn. J. Appl. Phys., 34, 797 (1995).

【2】 S. Nakamura, M. Senoh, S. Nagahama, N. Iwasa, T. Yamada, T. Matsushita, Y. Sugimoto, H. Kiyoku, “Room-temperature continuous-wave operation of InGaN multi-quantum-well-structure laser diodes with a long lifetime”, Appl. Phys. Lett., 70, 868 (1996).

【3】 M. A. Khan, M. S. Shur, J. N. Kuzunia, Q. chen, J. Burm, and W. Schaff, “Temperature activated conductance in GaN/AlGaN heterostructure field effect transistors operating at temperatures up to 300 °C”, Appl. Phys. Lett., 66, 1083 (1995).

【4】 O. Aktas, Z. F. Fan, S. N. Mohammad, A. E. Botchkarev, H. Morkoc, “High temperature characteristics of AlGaN/GaN modulation doped field-effect transistors”, Appl. Phys. Lett., 69, 3872 (1996).

【5】 P. Fischer, J. Christen, S. Nakamura, “Spectral electroluminescence mapping of a bule InGaN single quantum well light-emitting diode”, Jpn. J. Appl. Phys., 39, 129 (2000).