氮化鎵發光二極體的製作與特性量測

Abstract

在本論文中，我們以氮化鎵材料為樣品，使用五道罩幕圖案的光罩完成發光二極體與蕭基二極體元件微影過程的製作。對於發光二極體，藉由光頻譜的量測獲得元件的發光波長範圍。以及電流-電壓的量測了解元件的特性，如歐姆接觸的特定接觸電阻，使用兩種(TLM、CTLM)不同模型量測金屬與半導體間歐姆接觸的特性電阻；或對不同發光面積的發光二極體擬合logJ-V曲線分析元件理想因子、飽和電流密度或串聯電阻對發光二極體所造成的影響。以電流-電壓測量分析數種接面面積的蕭基元件的理想因子、串聯電阻、飽和電流密度及能障高度、或以電容-電壓量測其載子濃度與能障高度，並對製程與量測的結果作一些討論與分析。

In this study, we fabricated and characterized GaN light emitting diodes (LED) and Schottky diodes (SD). The structures for transmission line model (TLM) and circular transmission line model (CTLM) were prepared simultaneously to measure the sheet resistance of p-GaN epilayers and specific contact resistance of Ni-Au/p-GaN ohmic contacts. The luminescence spectra of LEDs are ranged from 450nm to 575nm, with peak wavelength at 500nm. As 20mA current flows, there exist about 3.3V voltage drop across LEDs. Various patterned LED structures give ideality factor 4.1-4.8, and series resistance 37-48 ohms. For Au-Ni/n-GaN Schottky diodes, the ideality factor is 1.4-1.7, the barrier height is 0.76-0.82eV for I-V measurement and is 1.21-1.42eV for C-V measurement.