在(100)矽基板上的二矽化鈷超導共面波導共振腔之製作與量測

Abstract

二矽化鈷 (CoSi2) 因其良好的導電特性、熱穩定性、與磊晶特性，已使用在矽積體電路中多年。在二矽化鈷/矽的低頻雜訊 (1/f noise) 研究中，可發現其雜訊量級比長在藍寶石基板 (sapphire) 上的鋁低二到三個數量級。二矽化鈷作為一種超導體，其低雜訊的優點可應用在許多超導相關元件上。我們將以二矽化鈷製作超導共面波導共振腔。樣品製作包含光微影製程、熱蒸鍍、及熱退火等技術。我們選擇共振頻率範圍為4~8 GHz。依此條件下設計光罩作為光微影製程使用。在氦3氦4稀釋致冷機 (溫度可達~10 mK) 的環境下，我們使用微波訊號產生器與微波訊號分析儀量測樣品的共振頻譜，再由共振頻譜分析負載品質因子(Loaded Q)、外部品質因子(External Q)與內部品質因子(Internal Q)。

Cobalt disilicide (CoSi2) has been used in silicon-based integrated circuits for many years because of its good conductivity, thermal stability, and epitaxial properties. In 1/f resistance noise study, we found that the noise level of CoSi2/Si heterostructure is much lower than that of Al on sapphire by 2 to 3 order of magnitude. As a superconductor, the ultralow noise feature of CoSi2 could be apply in many kinds of superconducting (SC) devices. We will make SC coplanar waveguide (CPW) resonator by CoSi2/Si. The fabrication process include optical lithography, thermal deposition, and thermal annealing. We choose the resonance frequency between 4 and 8 GHz and then design photomasks for optical lithography fabrication process. We will use microwave generator and analyzer to measure the resonance spectra of SC CPWs in dilution refrigerator (T ~ 10 mK). The load-ed Q, external Q and internal Q can be extracted from the resonance spectra.