以電漿輔助化學氣相沉積法成長多矽氧化矽暨研製金氧半發光二極體之製程與特性分析

Abstract

在本論文中，我們研究在1100度C的退火下，p-type矽基板上成長埋藏著奈米矽量子點的多矽氧化矽薄膜製作之金氧半二極體所發白光和近紅外電激螢光的不同機制。藉由改變基板溫度和感應式耦合電漿的大小，缺陷相關和矽量子點相關之載子傳輸與電激螢光光譜也被研究。基板溫度升高至350度C，感應式耦合電漿功率降至30W臨界值可沿著Si/SiOx介面成長出(100)晶面的三角形矽量子點。從變功率和變溫的顯微光激螢光光譜(micro-PL)中得知700到850 nm波段主要是由矽量子點表面的自我侷限激發子(self-trapped exciton)所貢獻。在比較未退火與退火過的多矽氧化矽薄膜的電激螢光光譜，確定奈米矽量子點相關的電激螢光波段在650到850 nm之間，而在較短波長的400到650 nm區間主要是可發光缺陷如弱氧鍵(weak-oxygen bond)、中性氧空缺形缺陷(neutral oxygen vacancy)和E'delta缺陷所貢獻。電子在高場下較易選擇流經缺陷，而這些缺陷可利用增加基板溫度和降低感應式耦合電漿功率來減少。利用此環境下成長之較少缺陷的多矽氧化矽薄膜可提供最穩定的近紅外電激螢光並有最長的元件壽命。然而這樣的奈米矽發光元件僅可提供約16 nW的輸出光功率。

The difference between white and near-infrared electroluminescences (EL) of the metal-oxide-semiconductor diodes fabricated on 1100oC-annealed Si-rich SiOx/p-Si substrate with buried pyramid Si quantum dots (Si-QDs) are characterized. By changing the substrate temperature and induced coupled plasma (ICP) power during the plasma enhanced chemical vapor deposition (PECVD) of Si-rich SiOx films, the effects of growth condition on the defect-related and Si-QD related carrier transport and EL spectroscopy are also investigated. By decreasing the ICP power to a threshold of 30 W, the (100)-oriented triangular Si-QDs significantly grows up the along Si/SiOx interface. From the power-dependent and temperature-dependent micro-PL spectra, it is concluded that the luminescent components at 700-850 nm is mainly contributed by the recombination in Si-QDs and self-trapped exciton (STE). After comparing the EL spectra of MOS diodes made on as-grown and annealed Si-rich SiOx, the Si-QD-related EL spectra at 650-850 nm is confirmed, whereas the EL spectra at shorter wavelengths (400-650 nm) is attributed to the radiative defects such as the weak-oxygen bond (415 nm), the neutral oxygen vacancy (NOV) defects (455 nm), and the E'delta defect (520 nm). These defects become an electron-preferred transporting path within the Si-rich SiOx film, whose densities are decreased with increasing substrate temperature or reducing ICP power. A nearly defect-free Si-rich SiOx sample can be grown under such condition, which contributes to a most stable near-infrared EL with longest lifetime although the power of purely Si-QD related EL at near-Infrared wavelengths is slightly lower (16 nW).