基于高介電常數(shù)薄膜的MEMS靜電式超級(jí)電容器制備及電學(xué)特性研究
發(fā)布時(shí)間：2019-06-09 12:26
【摘要】：MEMS超級(jí)電容器是能源存儲(chǔ)中的先進(jìn)領(lǐng)域,對(duì)于MEMS傳感器、醫(yī)療、交通等方面的發(fā)展發(fā)揮著越來越重要的作用。根據(jù)工作原理不同,MEMS超級(jí)電容器可以分為電化學(xué)超級(jí)電容器和靜電式超級(jí)電容器,電化學(xué)超級(jí)電容器近年來發(fā)展較快,其具有能量密度大、循環(huán)壽命長等優(yōu)點(diǎn)。相比于電化學(xué)超級(jí)電容器,靜電式電容器的能量密度較低,但是具有非常高的功率密度和可靠性。為了解決靜電式超級(jí)電容器能量密度低的問題,可以從兩個(gè)方面進(jìn)行研究:(一)增大電極的比表面積;(二)選用介電常數(shù)高的電介質(zhì)。本文分別從以上兩個(gè)方面進(jìn)行研究,并對(duì)MEMS靜電式超級(jí)電容器的制備工藝進(jìn)行了設(shè)計(jì)。具體研究內(nèi)容主要包括以下三個(gè)部分:1、為了增大MEMS靜電式超級(jí)電容器電極的比表面積,本文分別采用濕法刻蝕和干法刻蝕的方法在硅基底上制備三維凹槽陣列。對(duì)于濕法刻蝕,研究了掩膜版尺寸、刻蝕液配比等因素對(duì)刻蝕形貌的影響,并使用掃描電子顯微鏡(SEM)對(duì)凹槽陣列的形貌進(jìn)行了表征,最終得到的凹槽陣列比表面積增大約為76.9%。對(duì)于干法刻蝕,刻蝕得到高深寬比凹槽陣列的形貌以及可靠性通過SEM進(jìn)行表征,分析了在不同掩膜版尺寸下刻蝕凹槽的側(cè)壁垂直度及粗糙度,最終得到的凹槽陣列比表面積增大約為14倍。2、本文提出將CaCu_3Ti_4O_(12)(CCTO)薄膜應(yīng)用于MEMS靜電式超級(jí)電容器中,提高電容器的介電常數(shù)。首先,通過溶膠-凝膠法在硅基底上制備燒結(jié)溫度分別為700℃、800℃、900℃條件下的CCTO薄膜,分別采用掃描電鏡(SEM)、X射線衍射儀(XRD)和能譜儀(EDS)分析薄膜的表面形貌、結(jié)晶狀況以及物相組成,結(jié)果得到800℃燒結(jié)溫度下的CCTO薄膜質(zhì)量最佳。然后,使用半導(dǎo)體特性分析儀測試其電流-電壓(I-V)和電容-電壓(C-V)特性,得到薄膜的最大閾值電壓為47V,能量密度達(dá)到3.2J/cm~3。同時(shí),本文首次研究了高介電常數(shù)CCTO薄膜中存在的介質(zhì)充電現(xiàn)象,并分析了介質(zhì)充電對(duì)靜電式超級(jí)電容器性能的影響。3、對(duì)MEMS靜電式超級(jí)電容器的制備工藝進(jìn)行了設(shè)計(jì)。分別就電極制備、電介質(zhì)制備以及可靠性等方面進(jìn)行了討論。提出陽極氧化法制備電介質(zhì)薄膜的方法,并進(jìn)行了初步實(shí)驗(yàn)和電學(xué)特性分析。下一步將繼續(xù)開展實(shí)驗(yàn)進(jìn)行優(yōu)化和驗(yàn)證。
[Abstract]:MEMS supercapacitor is an advanced field of energy storage, which plays a more and more important role in the development of MEMS sensor, medical treatment, transportation and so on. According to the working principle, MEMS supercapacitors can be divided into electrochemical supercapacitors and electrostatic supercapacitors. Electrochemical supercapacitors have developed rapidly in recent years and have the advantages of high energy density and long cycle life. Compared with electrochemical supercapacitors, electrostatic capacitors have lower energy density, but have very high power density and reliability. In order to solve the problem of low energy density of electrostatic supercapacitors, two aspects can be studied: (1) increasing the specific surface area of the electrode; (2) selecting the dielectric with high dielectric constant. In this paper, the above two aspects are studied, and the preparation process of MEMS electrostatic supercapacitor is designed. The main research contents are as follows: 1. In order to increase the specific surface area of MEMS electrostatic supercapacitor electrode, three-dimensional groove array was fabricated on silicon substrate by wet etch and dry etch, respectively. For wet etch, the effects of mask size and etched liquid ratio on the etched morphology were studied, and the morphology of the groove array was characterized by scanning electron microscope (SEM). Finally, the specific surface area of the groove array increases by about 76.9%. For dry etch, the morphology and reliability of groove array with high aspect ratio are characterized by SEM. The sidewall verticality and roughness of etched groove under different mask sizes are analyzed. Finally, the specific surface area of the groove array is increased by about 14 times. 2. In this paper, CaCu_3Ti_4O_ (12) (CCTO) thin film is applied to MEMS electrostatic supercapacitors to improve the dielectric constant of the capacitors. Firstly, CCTO thin films were prepared on silicon substrate by sol-gel method at sintering temperatures of 700 鈩，
本文編號(hào)：2495554
[Abstract]:MEMS supercapacitor is an advanced field of energy storage, which plays a more and more important role in the development of MEMS sensor, medical treatment, transportation and so on. According to the working principle, MEMS supercapacitors can be divided into electrochemical supercapacitors and electrostatic supercapacitors. Electrochemical supercapacitors have developed rapidly in recent years and have the advantages of high energy density and long cycle life. Compared with electrochemical supercapacitors, electrostatic capacitors have lower energy density, but have very high power density and reliability. In order to solve the problem of low energy density of electrostatic supercapacitors, two aspects can be studied: (1) increasing the specific surface area of the electrode; (2) selecting the dielectric with high dielectric constant. In this paper, the above two aspects are studied, and the preparation process of MEMS electrostatic supercapacitor is designed. The main research contents are as follows: 1. In order to increase the specific surface area of MEMS electrostatic supercapacitor electrode, three-dimensional groove array was fabricated on silicon substrate by wet etch and dry etch, respectively. For wet etch, the effects of mask size and etched liquid ratio on the etched morphology were studied, and the morphology of the groove array was characterized by scanning electron microscope (SEM). Finally, the specific surface area of the groove array increases by about 76.9%. For dry etch, the morphology and reliability of groove array with high aspect ratio are characterized by SEM. The sidewall verticality and roughness of etched groove under different mask sizes are analyzed. Finally, the specific surface area of the groove array is increased by about 14 times. 2. In this paper, CaCu_3Ti_4O_ (12) (CCTO) thin film is applied to MEMS electrostatic supercapacitors to improve the dielectric constant of the capacitors. Firstly, CCTO thin films were prepared on silicon substrate by sol-gel method at sintering temperatures of 700 鈩，
本文編號(hào)：2495554
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