濺鍍法氧化銦錫在P型氮化鎵上之研究

Abstract

本篇論文是延續本實驗室以30奈米厚度的氧化銦錫層備製氮化鎵垂直共振腔面射型雷射為基礎，探討使用電子束蒸鍍法與濺鍍法成膜之氧化銦錫在P型氮化鎵上之不同及可改善空間。因為本實驗室為第一次使用30奈米厚度之濺鍍法氧化銦錫為氮化鎵垂直共振腔面射型雷射之透明導電層，其所得到的結果可能並非最佳效能，故此篇論文以改善使用30奈米氧化銦錫為透明導電層所得到的電性為主軸。我們比較了30奈米濺鍍法氧化銦錫在不同退火條件下的藍光穿透率、片電阻值及特徵接觸電阻值來判定最佳的退火條件，並且在氮化鎵發光二極體上，以不同成膜方式及退火條件之透明導電層來驗證其改善程度。我們發現使用快速退火系統在攝氏600度、退火300秒的條件下，30奈米濺鍍法氧化銦錫可得到最低的片電阻值(70.7Ω/□)及最低特徵接觸電阻值(0.0235 Ω•cm2)。以此退火條件作為氮化鎵發光二極體之透明導電層，濺鍍法較電子束蒸鍍法之輸出功率增加近28%。而與之前的攝氏600度、退火600秒條件相比較，300秒退火條件在片電阻值、特徵電阻值及氮化鎵發光二極體輸出功率均有所進步。這樣的結果可證明在P型氮化鎵上之30奈米氧化銦錫，濺鍍法較電子束蒸鍍法可得到較佳的效果，且有最佳的退火條件。以此結論即可以較佳的透明導電層條件，製作氮化鎵垂直共振腔雷射。

In this thesis, we investigate the difference between sputtered and E-gun ITO (Indium tin oxide) contact on P-GaN and try to improve the performance comparing to our previous works. It is based on the previous works of first time fabricating 30nm sputtered ITO as the TCL (transparent conduct layer) of GaN-based VCSEL (Vertical Cavity Surface Emitting Laser). It is possible that the performance value is not the best. Improving the performance of 30nm ITO as the TCL of VCSEL is our goal of this thesis. We used transmittance of blue ray、sheet resistance and specific contact resistance for indexes to find the better annealing condition. And we fabricated LED (Light Emitting diode) devices by using ITO as the TCL with different deposition method and different annealing conditions. We got minimum sheet resistance Rs (70.7 Ω/□) and minimum specific contact resistance ρc (0.0235 Ω•cm2) on 30nm sputtered ITO annealed by RTA at 600°C, 300s annealing. Base on this annealing condition, the output power of LED improved 28% by replacing TCL from E-gun ITO to sputtered ITO. Electrical performance also improved when comparing with the annealing condition in our previous work. By this result, we proved that sputtered ITO is the better option for VCSEL and 600°C 300s is the best annealing condition of 30nm sputtered ITO contact on P-GaN.