本文關(guān)鍵詞： 微熱板 ANSYS CNT@α-Fe_2O_3異質(zhì)結(jié)構(gòu) 氣體傳感器　出處：《吉林大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：在氣體傳感器領(lǐng)域,金屬半導(dǎo)體氧化物(MOS,Metal Oxide Semiconductors)氣體傳感器因具有靈敏度高、選擇性可調(diào)、可靠性高、全固態(tài)等特點(diǎn),一直是本領(lǐng)域的研究熱點(diǎn)。然而,不斷提高的環(huán)境標(biāo)準(zhǔn)以及傳感器特殊的使用環(huán)境對傳感器的性能提出了更加嚴(yán)苛的要求。目前,雖然基于旁熱式器件結(jié)構(gòu)的半導(dǎo)體氧化物氣體傳感器研究已經(jīng)取得較大進(jìn)展,但是如何進(jìn)一步提升傳感器對待測氣體的靈敏度和選擇性,降低傳感器的檢測下限和功耗仍然是該類傳感器面臨的重大挑戰(zhàn)。針對上述的關(guān)鍵科學(xué)問題,本論文從兩方面展開研究,首先是器件結(jié)構(gòu)的設(shè)計(jì)與開發(fā),具體是利用MEMS((Micro-Electro-Mechanical System)技術(shù)制作微熱板式器件,實(shí)現(xiàn)功耗的降低。其次是高性能敏感材料的設(shè)計(jì)與構(gòu)筑,具體是采用簡單的液相合成技術(shù)制備出CNT@α-Fe_2O_3復(fù)合異質(zhì)結(jié)構(gòu)氣敏材料,利用復(fù)合材料的結(jié)構(gòu)優(yōu)勢和不同氣氛下異質(zhì)結(jié)勢壘高度變化,實(shí)現(xiàn)傳感器靈敏度的提升。具體研究內(nèi)容如下:在器件結(jié)構(gòu)設(shè)計(jì)和制作方面,我們設(shè)計(jì)并制作了基于MEMS((Micro-Electro-Mechanical System)技術(shù)的微熱板(MHP,Micro hot-plate)式器件。利用ANSYS有限元分析對MHP進(jìn)行了熱穩(wěn)態(tài)及熱應(yīng)力分析,討論了加熱電極的形狀和背面硅層等因素對MHP懸膜溫度分布的影響。通過優(yōu)化結(jié)構(gòu)設(shè)計(jì),確立MHP采用蛇形加熱電極,背部保留0.5μm的硅層,器件的整體尺寸為2.0 mm×2.0 mm×0.4 mm。此后,利用MEMS工藝通過外協(xié)加工制作了懸臂梁式MHP,并用紅外熱像儀對其進(jìn)行了實(shí)際性能測試。測試結(jié)果顯示,MHP的熱場分布較均勻,高溫區(qū)主要集中在懸膜區(qū),實(shí)際MHP的加熱效率約為4.7℃/m W,實(shí)現(xiàn)低功耗。在高效敏感材料構(gòu)筑方面,結(jié)合α-Fe_2O_3優(yōu)異氣敏特性和碳納米管(CNT)大的比表面積及高的機(jī)械強(qiáng)度,利用簡單的液相合成技術(shù)制備出CNT@α-Fe_2O_3異質(zhì)結(jié)構(gòu)復(fù)合敏感材料。電鏡結(jié)果表明CNT@α-Fe_2O_3是一種以CNT為骨架,多晶的α-Fe_2O_3納米棒在其表面自組裝而成的一種棒狀異質(zhì)結(jié)構(gòu),長度約為幾個(gè)微米,直徑約500 nm左右。相比于單一的α-Fe_2O_3納米棒,CNT@α-Fe_2O_3復(fù)合異質(zhì)結(jié)構(gòu)具有更大的比表面積,從而增加表面吸附氧能力。CNT@α-Fe_2O_3復(fù)合材料氣敏特性測試結(jié)果表明。相比于單一α-Fe_2O_3結(jié)構(gòu),碳納米管的引入大幅度增強(qiáng)了復(fù)合異質(zhì)結(jié)構(gòu)CNT@α-Fe_2O_3傳感器對丙酮的敏感特性。在225℃下CNT@α-Fe_2O_3傳感器對100 ppm丙酮的響應(yīng)達(dá)到了34.6,檢測下限達(dá)到500 ppb,且具有快的響應(yīng)時(shí)間和良好的穩(wěn)定性。此外,基于CNT@α-Fe_2O_3復(fù)合異質(zhì)結(jié)構(gòu)的微熱板式氣體傳感器,相比旁熱式器件,其對丙酮的靈敏度和選擇性基本保持不變,但是其功耗在225℃時(shí)僅為44 m W,約為旁熱式器件的1/10(460 mW)。
[Abstract]:In the field of gas sensors, metal semiconductor oxide Oxide semiconductor sensors have high sensitivity and selectivity. High reliability, all solid state and other characteristics, has been the research hotspot in this field. However, the increasing environmental standards and the special use environment of the sensor put forward more stringent requirements on the performance of the sensor. Although much progress has been made in semiconductor oxide gas sensors based on side-heat devices, how to further enhance the sensitivity and selectivity of the sensors to gas measurement. Reducing the detection limit and power consumption of the sensor is still a major challenge for this kind of sensors. Aiming at the key scientific problems mentioned above, this paper studies from two aspects, the first is the design and development of the device structure. MEMS((Micro-Electro-Mechanical system technology is used to fabricate micro-hot plate device. The second is the design and construction of high performance sensitive materials, and the preparation of CNT @ 偽 -FeS2O3 heterostructure gas sensing materials by simple liquid phase synthesis technology. The sensitivity of the sensor can be improved by using the structure advantage of the composite material and the change of the barrier height of the heterojunction in different atmosphere. The specific research contents are as follows: in the aspect of device structure design and fabrication. We have designed and fabricated the micro hot plate based on MEMS((Micro-Electro-Mechanical system technology. Micro hot-plate device. The thermal steady state and thermal stress of MHP are analyzed by ANSYS finite element analysis. The influence of the shape of the heating electrode and the silicon layer on the temperature distribution of the MHP suspension film was discussed. By optimizing the structure design, the snake-shaped heating electrode was adopted in MHP and the silicon layer of 0.5 渭 m was retained in the back. The overall size of the device is 2.0 mm 脳 2.0 mm 脳 0.4 mm. After that, the cantilever MHP is fabricated by the MEMS process. The actual performance of MHP was tested by infrared thermal imager. The results showed that the thermal field of MHP was uniform, and the high temperature region was mainly concentrated in the suspension region. The actual heating efficiency of MHP is about 4.7 鈩，

本文編號：1456147