磷砷化鎵蕭基二極體的深能階暫態量測

Abstract

目前GaAsP三元化合物仍然是製造發光二極體的主要材料之一，由於材料 內深植能缺陷的存在降低了元件發光效率，所以如何改進品質對此材料在 元件及顯示器上的應用是重要的。本實驗利用深能階暫態量測系統研究N 型Te-GaAs0.35P0.65內部深植能缺陷。量測結果顯示，材料中有兩個多數 載子缺陷，定義為E1、E2， E1位於材料內部，活化能為0.12±0.03eV， 依據缺陷濃度對塊材空間分佈，推測其形成原因與Te及材料本植缺陷有關 ，E2位於金屬半導體接面上，活化能隨著不同金屬形成的蕭基二極體而改 變，在高溫退火下E2濃度逐漸降低或形成其它結構之缺陷，且在去氧化層 後消失，推測其形成原因與金屬及氧化層有關，最後量測一組隨長晶溫度 變化的樣品，其載子結合速率與LED輸出功率存在反比關係。 GaAs1-XPX III-V compound alloys is still the primary material for light-emitting diodes(LEDS) fabrication. The existence of deep level impurities reduces their luminescence efficiency. Therefore, it's important to improve the quality of the alloys for device and display applications. In this research ,deep level transient spectroscopy (DLTS) was used to determine the deep level traps. In all the studied,there are two electron traps found ,labeled E1&E2. E1 is a bulk defect and has an activation energy Ea=0.12±0.03eV. According to the depth profile, E1 possibly resulted from Te and native defect. E2 is a surface defect and can be found only near the interface between the metal and the semiconductor.This surface defect can be reduced and change structure by high temperature annealing. Samples grown at different temperatures have also been measured and carrier recombination rate was found inversely proportional to the LED output power.