以新穎磁波濺鍍矽/氧化鉺覆置氧化矽靶材成長摻鉺富矽二氧化矽發光材料

Abstract

在本論文中，我們利用新穎方法使用一氧化矽靶材有效減少氧的含量，並使用矽及氧化鉺覆置於靶材上，配合磁波濺鍍機，在矽:氧化矽:氧化鉺比例為35:52:13下成長摻鉺富矽二氧化矽發光材料，並研究其最佳的退火溫度及時間。我們利用532 nm，120W雷射激發摻鉺富矽二氧化矽材料，在1000oC、240 min的退火條件下，在1535 nm處得到最強的紅外光螢光光譜，主要是由奈米矽晶吸收激發能量，將能量轉移給鉺離子後，由第一激發態至基態所發出的紅外光光譜。除此之外，我們亦研究在不同溫度及不同時間下，影響此材料發光效率的原因。另外，我們在不同濺鍍條件下成長的摻鉺富矽二氧化矽材料，研究其所主宰的因子，實驗顯示，我們成長此系列材料中，其主要的因素為在材料中鉺離子的含量。 除了在螢光光譜的研究外，我們也研究材料在電性上的特性。我們利用BOE蝕刻溶夜控制摻鉺富矽二氧化矽層的厚度，來研究不同厚度下電流電壓特性。我們發現由於BOE溶液對此摻鉺富矽二氧化矽的蝕刻為非等向性蝕刻，蝕刻深度不同，致使其電場分佈不均勻，造成原件操作在低電場下極易崩潰燒毀。另外，我們亦研究在不同退火時間下電流電壓的特性，發現其啟動電場隨退火時間增加而增加，此係由於在退火時間增加下，二氧化矽的結構強度亦隨之增加所致。而啟動時電流密度對退火時間的變化趨勢與奈米矽晶對退火時間趨勢相符，此係由於在此金氧半原件中，奈米矽晶為電流注入的主宰因子，奈米矽晶的濃度愈高，電流愈易注入。然而，我們從測量可見光及紅外光功率實驗時，由於奈米矽晶密度不夠，尚無法使電流有效注入，因而無法得到電激螢光光譜。另外，由於電流注入時所誘發的熱效應，使我們的原件無法在高電場作用下操作。

In this thesis, we demonstrated a novel method to reduce the oxygen contents from the target, which is instead of the silicon dioxide (SiO2) target by the silicon monoxide (SiO) target. The thermal annealed RF magnetron sputtering-grown Er:SiOx with the area ratio of Si: SiO: Er2O3 = 35: 52: 13 is demonstrated. The optimized annealing temperature and time for Er:SiOx films are also observed. Strong IR-PL peak by using the pumping source of a 532 nm DPSS green laser, at the wavelength of 1535 nm is attributed to the energy transfer from nc-Si to the intra-4f transitions between the first excited state (4I13/2) and the ground state (4I15/2) of Er3+ ion. The annealing conditions of time and temperature are demonstrated to find out the factors which affect the IR-PL intensity. Lower annealing temperature and shorter annealing time cause the decrease of IR-PL intensity, which is attributed to the less density of Er3+ and nc-Si. Higher annealing temperature causes the decrease of IR-PL intensity, which is attributed to the less density of Er3+. Moreover, longer annealing time also causes the decrease of IR-PL intensity, which is attributed to the less density of nc-Si. High temperature process causes the segregation of erbium ions and contributes the decrease of the Er3+ density. Long duration process causes the decrease of nc-Si, which is attributed to the limitation of the excess Si. The maximum IR-PL intensity at the wavelength of 1535 nm is observed from the Er:SiOx sample annealed at 1000oC for the 240 min. The experiments under the RF sputtering power varying from 80 W to 170 W are also demonstrated. The maximum density of Si and Er are occurred under the RF power of 170W and 100W, respectively. The more Si and Er contents indicate the larger amount of the density of nc-Si and Er3+, respectively. In the RF sputtering power dependent experiments the dominative factor is the concentration of erbium.