本文選題：氮化鋁 + 壓電性　； 參考：《中國科學院研究生院(長春光學精密機械與物理研究所)》2014年博士論文

【摘要】：氮化鋁(AlN)薄膜材料作為一種重要的III-V族化合物，具有高聲波速、高壓電性以及良好的化學穩(wěn)定性等優(yōu)點，使得AlN壓電薄膜在高頻聲波諧振器、濾波器、傳感技術(shù)等領(lǐng)域備受關(guān)注。反應磁控濺射可以實現(xiàn)高質(zhì)量AlN壓電薄膜的低溫快速生長，在實際應用中被廣泛采用。但由于材料性能對工藝參數(shù)極為敏感以及壓電薄膜性能表征等問題，使得該材料的高質(zhì)量制備尚未形成標準工藝。本文圍繞AlN壓電薄膜的反應磁控濺射制備方法及性能表征開展了以下研究： 根據(jù)電介質(zhì)的極化理論，研究了AlN材料晶體結(jié)構(gòu)與其內(nèi)部極化的關(guān)系，分析AlN材料壓電性的影響因素。同時，利用固體中的彈性波理論計算了不同偏振態(tài)下的聲波沿AlN晶體各晶軸傳播時的相速度,并得出c-軸取向AlN壓電薄膜具有較高的壓電性以及高縱波速的結(jié)論。 為了獲得提高AlN壓電薄膜c-軸取向的途徑，論文通過Berg模型對反應濺射過程氮氣流量與其偏壓關(guān)系進行了模擬，并預測了靶材的工作狀態(tài)。通過在硅襯底上制備AlN壓電薄膜的系列實驗，對影響該材料質(zhì)量的重要工藝參數(shù)進行了深入細致的研究；由以上研究可知，當靶材處于金屬態(tài)與中毒態(tài)的過渡區(qū)域時，薄膜既可以獲得較好質(zhì)量，，而且還可以維持一定的生長速率； 借助于X射線衍射技術(shù)、掃描電子顯微鏡、原子力顯微鏡等手段，建立了可對不同制備條件下AlN壓電薄膜的晶體結(jié)構(gòu)與形貌的高準確表征的方法。同時提出了一種新型的、更精準的測試模型，利用該模型和壓電響應力顯微鏡等對AlN薄膜的壓電性進行測試和驗證。 對不同濺射工藝參數(shù)下制備的AlN壓電薄膜晶體結(jié)構(gòu)、表面形貌以及表面粗糙度的分析發(fā)現(xiàn)，在濺射功率為460W，濺射氣壓為3.0mTorr，氮氣流量比為85%，薄膜生長溫度為400℃時，可制備出(002)擇優(yōu)取向的高質(zhì)量AlN壓電薄膜，薄膜(002)晶面搖擺曲線的半高寬(FWHM)優(yōu)于1.70°；在對本文制備的AlN薄膜的壓電性定量分析過程中，利用本文所提模型測得AlN薄膜的縱向壓電常數(shù)：d33=(4.220.34) pm/V，該數(shù)值與已報道方法測得的AlN薄膜的縱向壓電常數(shù)之間的偏差小于5.7%，從而驗證了本模型的合理性與準確性。
[Abstract]:As an important III-V family compound, AlN thin film material has the advantages of high acoustic velocity, high voltage and good chemical stability, which makes AlN piezoelectric film in high frequency acoustic wave resonator, filter, etc. Sensing technology and other fields have attracted much attention. Reactive magnetron sputtering (RMC) can realize the rapid growth of high quality AlN piezoelectric films at low temperature and is widely used in practical applications. However, due to the high sensitivity of material properties to process parameters and the characterization of piezoelectric film properties, the high quality preparation of the material has not yet formed a standard process. In this paper, the preparation and characterization of AlN piezoelectric films by reactive magnetron sputtering have been studied as follows: Based on the polarization theory of dielectric, the relationship between crystal structure and internal polarization of AlN material is studied, and the influencing factors of piezoelectric properties of AlN material are analyzed. At the same time, the phase velocities of acoustic waves propagating along each axis of AlN crystal under different polarization states are calculated by using the elastic wave theory in solids, and the conclusion that c-axially oriented AlN piezoelectric thin films have high piezoelectric properties and high longitudinal wave velocity is obtained. In order to obtain a way to improve the c-axis orientation of AlN piezoelectric films, the relationship between nitrogen flow rate and bias voltage in reactive sputtering process was simulated by Berg model, and the working state of the target was predicted. Through a series of experiments on the preparation of AlN piezoelectric thin films on silicon substrates, the important technological parameters affecting the quality of the material are studied in detail. From the above studies, it is known that when the target material is in the transition region between metal state and toxic state, The film can not only obtain better quality, but also maintain a certain growth rate. By means of X-ray diffraction, scanning electron microscope and atomic force microscope, a method was established to characterize the crystal structure and morphology of AlN piezoelectric films under different preparation conditions. At the same time, a new and more accurate testing model is proposed. The piezoelectric properties of AlN thin films are tested and verified by using the model and piezoelectric response force microscope. The crystal structure, surface morphology and surface roughness of AlN piezoelectric thin films prepared by different sputtering process parameters were analyzed. It was found that when sputtering power was 460 W, sputtering pressure was 3.0 m Torr, nitrogen flow ratio was 85 鈩

本文編號：1809839