GaN基隧穿器件的制备及特性的研究

发布时间：2018-01-03 18:38

  本文关键词：GaN基隧穿器件的制备及特性的研究　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： MOCVD p-Ga N PITJ p-Ga N/n-Zn O

【摘要】：目前,Ga N基LED已经进入到了市场化发展阶段,但是其在许多方面还存在着不足,如:(1)Ga N的p型载流子浓度相对较低、且电极的接触电阻较大;(2)量子阱(MQWs)中存在量子限制斯塔克效应,使得电子/空穴对的复合几率变小;(3)高In组分的In Ga N生长困难,且缺陷很多,从而降低了Ga N基LED的发光效率。近年来,国际上很多课题组开展了利用极化诱导隧穿结(PITJ:polarization-induced tunneling junction)提高Ga N基LED发光效率的研究工作。在Ga N基LED中引入PITJ具有如下优点:(1)隧穿作用可以增加器件的空穴注入;(2)n-Ga N的横向扩展电阻要低于p-Ga N,以n-Ga N代替p-Ga N作为横向电流传输层,可以减小串联电阻,提高扩展电流;(3)n-Ga N电极的接触电阻要小于p-Ga N,以n-Ga N代替p-Ga N作为电极的欧姆接触层,可以避免p-Ga N欧姆接触产生的吸收损耗,从而提高Ga N基LED的发光特性。本论文根据Ⅲ族氮化物的极化和隧穿理论,开展了Ga N基隧穿器件的制备及特性研究。具体的研究内容如下:1.利用MOCVD技术,开展了高质量Mg掺杂p-Ga N薄膜的研究与制备工作。主要研究了p-Ga N薄膜的生长温度、Mg源流量和退火温度对其晶体质量、载流子浓度及电阻率的影响。通过优化生长参量,我们制备了高质量的p-Ga N薄膜。在生长温度为985℃、Mg源流量为250sccm、退火温度为900℃时,p-Ga N薄膜的(0002)晶面XRD摇摆曲线半峰宽(FWHM)仅为~250arcsec,空穴浓度可以达到5.2×10~17/cm~3。2.基于极化理论和隧穿理论,开展了极化诱导隧穿结的研究与制备工作。主要研究了Al Ga N极化层的厚度和组分对PITJ结构特性和电学性质的影响。通过优化生长参量,我们制备了具有反向整流特性的p-Ga N/Al Ga N/n~+-Ga N极化诱导隧穿结。在Al Ga N极化层厚度为10nm、组分为0.1时,PITJ的电学性质最佳。此时,在5V的反向电压下,可以获得8.57m A的反向隧穿电流。3.制备了PITJ p-Ga N/n-Zn O异质结LED和p-Ga N/n-Zn O异质结LED,深入研究了极化效应和隧穿效应对p-Ga N/n-Zn O异质结LED光电特性的影响。相较于p-Ga N/n-Zn O异质结LED,PITJ p-Ga N/n-Zn O异质结LED表现出更高的发光强度和更好的发光稳定性。在20m A电流下,带有PITJ结构的p-Ga N/n-Zn O异质结LED的发光强度是普通p-Ga N/n-Zn O异质结LED的1.4倍;连续工作8h后,PITJ p-Ga N/n-Zn O异质结LED的发光强度只减弱3.5%。
[Abstract]:At present, Ga-N-based LED has entered the stage of market-oriented development, but it still has some shortcomings in many aspects, such as the relatively low concentration of p-type carriers at 1: 1 Ga-N. The contact resistance of the electrode is larger; (2) the existence of quantum confinement Stark effect in quantum well MQWs makes the recombination probability of electron / hole pairs smaller; (3) the in Ga N with high in composition is difficult to grow and has many defects, which reduces the luminescence efficiency of Ga N based LED in recent years. Many international research groups have developed polar-induced tunneling junction (PITJ: polarization-induced tunneling junctions). In order to improve the luminescence efficiency of gan based LED, the introduction of PITJ into gan based LED has the following advantages: 1) tunneling can increase the hole injection. The transverse spread resistance of n-Ga N is lower than that of p-Ga N. The series resistance can be reduced and the spreading current can be increased by using n-Ga N instead of p-Ga N as the transverse current transport layer. The contact resistance of n-Ga N electrode is smaller than that of p-Ga N electrode, and the ohmic contact layer of p-Ga N electrode is replaced by n-Ga N electrode. The absorption loss caused by p-Ga N ohmic contact can be avoided and the luminescence characteristics of Ga N based LED can be improved. The fabrication and characteristics of gan based tunneling devices are studied. The specific research contents are as follows: 1. Using MOCVD technology. The research and preparation of high quality mg doped p-Ga N thin films were carried out. The growth temperature, mg source flux and annealing temperature of p-Ga N thin films on their crystal quality were studied. By optimizing the growth parameters, high quality p-Ga N thin films were prepared, and the flux of mg source was 250 SCcm at 985 鈩，

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