本研究以射頻磁控濺鍍法製作氮氧化鉭-Ta(N,O)薄膜。藉由鍍膜參數的調變，如鍍膜功率、基板溫度、通入反應性氣體比率等參數的變化，以探討薄膜在微觀結構上的變化，進而在光學上、熱學上以及在機械性質上的表現，以期在光碟用之介電層開發上有突破性的進展。
在室溫下所製備之氮氧化鉭薄膜呈現非晶質（amorphous）的結構，在經過700oC、一個小時、氬氣氣氛下退火或700oC、五分鐘快速升溫退火處理後，仍能保持非晶質結構。 經由場發射掃瞄式電子顯微鏡（FE-SEM）做截面掃瞄，薄膜顯微結構為柱狀成長結構。在薄膜表面粗糙度之均方根值方面，當基板不升溫（室溫）時，約為1.288±0.01 nm，經過800oC快速升溫退火處理後，約為8.479±0.01 nm；當基板溫度升至300oC時，約為0.217±0.01 nm。

在光學性質方面，波長範圍633nm至780nm，經過不同氮氧比例調變而得之氮氧化鉭薄膜，隨著氮氣通入比率增加其折射係數（n），由2.2變化至1.9，反射率多在 0.15 到 0.35 之間，穿透率 在0.75 到 0.95 之間。光學結構的變化以結構變化予以合理解釋。

在機械性質方面，利用微機電製程之微懸臂樑方法，來檢測薄膜之殘留應力及熱膨脹係數。在薄膜初鍍時，經由通入氧、氮流量的變化，薄膜之殘留應力皆為壓應力；當彈性係數變化範圍在150到200 GPa，其變化範圍由12.5 MPa到0 MPa，而熱膨脹係數則由7.5 x 10–7 /oC到 7.5 x 10–6 /oC。另外，利用奈米壓痕器來檢測薄膜的硬度及彈性行為。當普松比為0.3時，硬度變化由6 GPa到39 GPa，彈性係數由130 GPa到179 GPa。

經由鍍膜參數的調變，非晶質氮氧化鉭薄膜的光學折射係數高(>1.9)、殘留應力範圍與GeSbTe薄膜相當，熱膨脹係數可變化範圍大且多優於(ZnS)80(SiO2)20薄膜。機械強度方面，氮氧化鉭薄膜具有較(ZnS)80(SiO2)20薄膜高的彈性係數及硬度，對於記錄層記錄點因受熱變形後之調變以及抵抗能力強，將有助於記錄點邊緣的變形抵抗，以增強光學對比及覆寫能力。

In this study, the tantalum oxynitride-Ta(N,O) films were prepared by RF magnetron sputtering. By tuning the sputtering parameters, such as RF power, substrate temperatures, sputtering gas ratios such as like the N2/O2 flow ratio and the Ar fraction (Ar/(Ar+N2+O2)), the effects of microstructure on optical properties, thermal properties and mechanical properties were investigated. When the film was deposited at room temperature, it showed an amorphous phase, and remained amorphous after annealing at 700oC for one hour by using conventional furnace in Ar ambient, so as the rapid thermal annealing above 700oC for 5 min. The growth characteristic showed in the form of columnar, and the root mean square roughnesses of as-deposited films deposited at 25oC and 300oC, respectively, were 1.288±0.01 nm and 0.217±0.01 nm, and increased to 8.479±0.01 nm by RTA at 800oC for 5 min.
When the N2/O2 flow ratio varied from 4, 1 to 0.25, the crystalline tantalum nitride particles embedded in a continuous, ring-like and granular amorphous matrix were observed and the particle size for both of the tantalum nitride and tantalum oxide phase grew gradually. In the wavelength ranging from 633nm to 780nm, the refractive index (n) of the tantalum oxynitride films deposited on silicon wafer decreased from 2.2 to 1.9 as increasing N2/O2 flow ratios. The reflectance (0.15 to 0.35) and the transmittance (0.73 to 0.90) of studied films deposited on glass substrate changed with sputtering parameters. The microcantilever beam method was used to study the residual stress and thermal expansion coefficient. All the as-deposited films showed a compressive state and the CTE values varied with different N2/O2 flow ratios from 12.5 to 0 MPa and 7.5 x 10–7 /oC to 7.5 x 10–6 /oC, respectively. Compared with the values of (ZnS)80(SiO2)20 films (4.78±0.29 GPa and 39.5±1.2Gpa), the hardness and the elastic constant of Ta(N,O) films were ranging from 6~39±0.5 GPa and 130~179±3.2 GPa, respectively. The harder Ta(N,O) film without sulfur inter-diffusion will be a more suitable candidate as the dielectric layer of optical recording disk.

Keywords: RF sputter, tantalum oxynitride, columnar structure, microcantilever beam method, nanoindentation method, thermal traveling wave method, optical recording disk

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