本文選題：SiC薄膜 + 磁控濺射技術(shù)　； 參考：《南京航空航天大學(xué)》2017年碩士論文

【摘要】：SiC作為如今越來越熱門的第三代寬禁帶半導(dǎo)體材料,擁有熱導(dǎo)率高、飽和電子漂移速度高、禁帶寬度大、擊穿電場高、熱穩(wěn)定性高等一系列特點(diǎn),因此在航天航空、核電以及大功率高頻器件環(huán)境中具有廣闊的應(yīng)用前景。本課題選擇100方向的單晶Si以及0001方向的單晶藍(lán)寶石(α-Al2O3)兩種襯底,利用射頻磁控濺射技術(shù)制備了適合不同應(yīng)用條件下的六方晶型SiC薄膜。研究了不同工藝條件對薄膜的物相結(jié)構(gòu)、表面及斷面形貌、電阻溫度特性的影響,并對不同襯底上的薄膜元件的綜合電學(xué)特性進(jìn)行了總結(jié)。利用射頻磁控濺射技術(shù)在100方向的單晶Si及單晶Si/SiO2(200nm)襯底上生長SiC薄膜。通過過渡層、沉積溫度、退火前后等工藝參數(shù)的調(diào)控,在沉積溫度750℃等條件下,單晶Si/SiO2(200nm)襯底上,由于薄膜與襯底晶格失配得到一定程度的釋放,獲得了具有一定取向的六方晶型SiC薄膜。薄膜熱運(yùn)輸激活能為0.16eV,由擴(kuò)展態(tài)導(dǎo)電機(jī)制主導(dǎo)。過高的沉積或退火溫度,都會使該襯底上的SiC薄膜中Si、C原子發(fā)生擴(kuò)散、產(chǎn)生雜相,影響其致密性和電阻溫度穩(wěn)定性。同時,該SiC薄膜在-100~250℃擁有很高的熱敏常數(shù)B(1400~2000K),經(jīng)多次重復(fù)測試后發(fā)現(xiàn),不同溫度下的電阻誤差僅±5%,適合制成高精度型熱敏電阻器和溫度傳感器。由于單晶Si襯底適用溫度的局限性,為了能在更高溫度下應(yīng)用該SiC薄膜的電學(xué)特性,利用射頻磁控濺射技術(shù)在0001方向的單晶藍(lán)寶石襯底上生長SiC薄膜。在沉積溫度750℃、濺射氣壓純氬1Pa、射頻功率100W、1000℃氬氣氣氛中快速熱退火10min等工藝條件下,薄膜開始向晶態(tài)轉(zhuǎn)變,XRD中出現(xiàn)了六方晶型的6H-SiC衍射峰。但由于襯底的巨大拉應(yīng)力,薄膜晶格畸變,衍射峰都向小角度方向偏移了1~2°,并且薄膜導(dǎo)電機(jī)制偏向于擴(kuò)展態(tài)導(dǎo)電,熱運(yùn)輸激活能為0.21eV。同時,該SiC薄膜電阻穩(wěn)定變化區(qū)間為-100℃~425℃,熱敏常數(shù)B變化幅度大(960K~4500K),不同溫度下的電阻經(jīng)過多次重復(fù)測試,誤差±8%,適合制成高溫型熱敏電阻器和溫度傳感器。為了緩解SiC薄膜與藍(lán)寶石襯底間的晶格失配及熱膨脹系數(shù)的差異,在藍(lán)寶石襯底與SiC薄膜中間嘗試加入了一層Si-O-C中間過渡層,使得SiC薄膜衍射峰向小角度方向偏移的程度減緩了0.2~0.4°,薄膜能更穩(wěn)定地生長,膜厚增加了0.1μm,薄膜熱運(yùn)輸激活能與電阻溫度特性變化趨勢未變,含有過渡層的膜基結(jié)合力比不含過渡層的膜基結(jié)合力提高了1N。
[Abstract]:As the third generation wide band gap semiconductor material, SiC has a series of characteristics, such as high thermal conductivity, high velocity of saturated electron drift, wide band gap, high breakdown electric field, high thermal stability and so on. Nuclear power and high-power high-frequency device environment have broad application prospects. In this paper, the hexagonal crystalline SiC thin films were prepared by RF magnetron sputtering on 0001 direction single crystal sapphire sapphire (偽 -Al 2O 3) and 100 direction single crystal Si substrates. The effects of different process conditions on the phase structure, surface and cross-section morphology, resistance temperature characteristics of the films were studied. The comprehensive electrical properties of the thin film elements on different substrates were summarized. SiC thin films were grown on Si and Si / SiO _ 2O _ (200 nm) substrates by radio frequency magnetron sputtering (RF magnetron sputtering). By controlling the process parameters such as transition layer, deposition temperature, annealing and so on, the single crystal Si / SiO _ 2O _ 2O _ (200 nm) substrate is released to a certain extent due to the mismatch between the film and the substrate lattice at the deposition temperature of 750 鈩，

本文編號：1818730