電流導向結構對氮化銦鎵�氮化鎵發光二極體發光效率改善之研究

Abstract

本研究中，我們使用離子佈植技術來製作電流導向結構。透過此電流導向結構來改變電流的流向，改善元件的電流擴散並降低電流群聚效應。藉由減少由量子井所放出的光被金屬電極所吸收或反射，我們可以提高光汲出效率以及光輸出的強度。離子佈植技術具有能夠改變材料摻雜濃度的特性，因此我們在傳統的製程步驟中加入一個佈植的程序，將欲製作電流導向結構之P型氮化鎵的材料區域有效摻雜濃度降低。因此其有效濃度將低於周遭區域而形成一個相對阻抗值較大的區域。再利用電流傾向於流經阻抗值較低的區域而強制提高金屬電極所覆蓋區域以外的電流密度。由實驗結果我們發現在20mA的輸入電流下，最高可以將光輸出功率提高達到30.3%。

In this research, we fabricate the current diverting structure by using ion implantation technology. With this structure, we can change the current flowing path to improve current spreading of the device and reduce current crowding effect. By reducing the light absorption and reflection by metal electrodes, we can increase the light extraction efficiency and light output power. Ion implantation technology has the property of changing the doping concentration of the material. Therefore we add a step of implantation in the conventional process steps to reduce the doping concentration of the p-type GaN where we want to fabricate the current diverting structure. By this, we have an area with lower concentration compared with the surrounding area and as a result, the higher resistance. As we know that the current tends to flow through a path with lower resistance, we can increase the current density of the area outside of the metal electrode. The experimental results show that at 20mA current injection, the maximum of output power enhancement is 30.3%.