奈米矽摻雜碳化矽金氧半發光二極體

Abstract

本論文中，利用 PECVD 隨著調變(甲烷+矽甲基烷)/(甲烷+矽烷+矽甲基烷+氬氣)的流量比成長，得到富矽碳化矽與富碳碳化矽薄膜。由 XPS 的分析發現在相同的流量比下，成長碳化矽薄膜前通入氬氣降低腔體氧氣的含量，可以把碳化矽薄膜的氧含量從 33.9 降到 9.2%，得到比較高的矽含量以及比較低的 Igraphite-like sp2 C-C /Idiamond-like sp3 C-C 比值，有效降低薄膜電阻率以及捕捉載的缺陷密度。由於薄膜碳含量的增加，造成 PL 光譜隨著組成比提高產生藍位移以及 FTIR 頻譜中 Si-CH3 從896 cm-1位移到 922 cm-1 。經由熱退火處理後由於 Si-Si/Si-C 鍵解量改變以及晶格不匹配，分別造成薄膜厚度變薄以及薄膜表面略為龜裂。當流量比從 90%降低 70%時，碳化矽薄膜片電阻從 4.8×108 (Ω/sq.) 降低到3.18×106 (Ω/sq.)。 本研究亦利用磊晶富矽碳化矽薄膜成功製作了富矽碳化矽的發光二極體元件，其結構為 Al/p-Si/i-SiC with Si-nc/n-SiC/ITO。經由增加基板溫度從 300oC 到 650oC優化薄膜結晶性且組成比不隨薄膜深度改變，使得熱退火過程中避免氧原子侵入到碳化矽薄膜。高機板溫度磊晶元件可分別增強元件輸出功率從 5.4 nW 增加到 22.7 nW、優化能量轉化效率由 1.6×10-8 增加到 7.2 ×10-8以及提高外部量子效率由 1.6×10-7 增加到 2.5×10-7。EL 頻譜分析得到此富矽碳化矽發光二極體為中心波長570 nm 譜寬約 240nm 的橘黃色光源。

We demonstrate the deposition and characterization of silicon-rich and carbon-rich amorphous silicon carbide films by plasma-enhanced chemical vapor deposition (PECVD). The oxygen quantity reduces from 33.9 to 9.2% utilizing Ar purge to eliminate the residual oxygen gas in the chamber of PECVD. From the XPS analysis, it has higher composition ratio x, lower ratio of Igraphite-like sp2 C-C /Idiamond-like sp3 C-C with Ar purge result in lower resistivity and reducing electronic defects under the some fluence ratio g. From the PL spectrum and analysis of FTIR the peak wavelength blue shift with and the rocking modes of Si-CH3 shifts from 896 to 922 cm-1 with the fluence ratio, respectively, due to Carbon atoms increases in the a-SixC1-x films. After annealing treatment, the thickness decreases and crack due to the structural relaxation and lattice mismatch, respectively. The rS and Rc increase from 3.18×106 to 4.8×108 (Ω/□) and 2.55×105 to 1.97×107 (Ω) surveyed by Transmission-Line-Model (TLM) as increasing the fluence ratio g = 70 to 90%. We prepare the Al/p-Si/i-SiC with Si-nc/n-SiC/ITO device with the different depositing substrate temperature. From the TEM result, the average diameter of the Si-nc is 2.7±0.2 nm embedded in silicon-rich SiC matrix. By combination annealing treatment under 1050oC for 30 min and PH3 doping, the resistivity decrease from 3.48×10-3 to 8.98×10-5 Ω-cm with increasing the ratio of PH3/(SiH4+CH4+SiH3CH3+Ar) from 0.6% to 5%. As depositing substrate temperature increase from 300oC to 650oC, the optical output power, power conversion ratio (PCR), and external quantum efficiency (EQE) increase from 5.4 nW to 22.7 nW, 1.6×10-8 to 7.1×10-8, and 1.6×10-7 to 2.5×10-7, respectively. It is due to the stable composition ratio x as function of vertical deep in the SixC1-x film, preventing the SixC1-x film from the incorporation of oxygen, and making the SixC1-x film crystallize after annealingtreatment, respectively. The result of the electroluminescence (EL) spectrum show the peak position is 570 nm which agree with the EL pattern.