【摘要】：硅是地球上儲藏最豐富、使用最廣泛的半導(dǎo)體材料,在微電子領(lǐng)域已有大量應(yīng)用。最近二十多年來,硅材料在微機電系統(tǒng)中也有廣泛應(yīng)用,如人們研制成功各種的硅微型壓力傳感器、硅微尺度的加速度計。熱學(xué)性質(zhì)是硅材料的一種基本物理性質(zhì),對它們的了解和掌握將有助于我們成功設(shè)計和可靠使用基于硅材料的各種微機電系統(tǒng)構(gòu)件。熱膨脹作為硅單晶材料的最重要的一種熱學(xué)性質(zhì),長期以來得到了人們充分的理論與實驗研究。人們通過實驗,發(fā)現(xiàn)它在低溫下有負熱膨脹現(xiàn)象,研究表明,采用Stillinger-Weber模型,人們不能在低溫下計算得到負熱膨脹系數(shù)。因此應(yīng)用該模型不能解釋硅單晶材料的低溫下有負熱膨脹的物理機制,必須進行修正。本文將揭示硅晶體在低溫下具有負熱膨脹性質(zhì)的微觀機制,對Stillinger-Weber模型加以修正,使其能應(yīng)用于硅單晶的熱膨脹研究,為微型機電系統(tǒng)構(gòu)件的合理設(shè)計和可靠使用提供理論依據(jù)。該研究方法同樣適用于其他金剛石結(jié)構(gòu)的晶體材料的熱膨脹性質(zhì)研究,具有普適性。本文的主要內(nèi)容包括:1.介紹硅材料其熱物性尤其是熱膨脹性質(zhì)的理論與實驗研究現(xiàn)狀及研究意義。2.介紹Stillinger-Weber模型下硅單晶分子動力學(xué)模擬的基本原理以及分子動力學(xué)模擬的主要步驟和流程,并加以實驗數(shù)據(jù)進行模擬。3.采用晶格動力學(xué)的方法推導(dǎo)了硅單晶的熱膨脹系數(shù)與原子間兩體作用和三體作用的三階力常數(shù)之間的關(guān)系式,通過微擾理論的運用推導(dǎo)出硅單晶的晶格常數(shù)和熱膨脹系數(shù)的公式,由此探索硅單晶在低溫下具有負熱膨脹性質(zhì)的物理機制。4.對硅單晶熱膨脹性質(zhì)的晶格動力學(xué)模擬結(jié)果、分子動力學(xué)模擬結(jié)果以及實驗數(shù)據(jù)結(jié)果進行對比,并得出相關(guān)結(jié)論:硅單晶在低溫下確實存在負熱膨脹性質(zhì),引起該性質(zhì)的根本原因是三階力常數(shù)為正。
[Abstract]:Silicon is the most abundant and widely used semiconductor material on earth and has been widely used in the field of microelectronics. In recent twenty years, silicon materials have been widely used in MEMS, such as various silicon micro pressure sensors and silicon micro scale accelerometers. Thermal properties are one of the basic physical properties of silicon materials. Understanding and mastering them will help us to design and use various MEMS components based on silicon materials successfully. Thermal expansion, as one of the most important thermal properties of silicon single crystal, has been studied in theory and experiment for a long time. It is found that it has negative thermal expansion at low temperature through experiments. It is shown that the Stillinger-Weber model can not be used to calculate the negative thermal expansion coefficient at low temperature. Therefore, the model can not explain the physical mechanism of negative thermal expansion of silicon single crystal materials at low temperature, and must be modified. In this paper, the microcosmic mechanism of negative thermal expansion of silicon crystal at low temperature is revealed, and the Stillinger-Weber model is modified so that it can be applied to the study of thermal expansion of silicon single crystal, which provides a theoretical basis for the rational design and reliable use of micro electromechanical system components. This method is also suitable for the study of thermal expansion properties of other diamond crystal materials. The main contents of this paper include: 1. The present situation and significance of theoretical and experimental research on thermal physical properties, especially thermal expansion properties of silicon materials are introduced. The basic principle of molecular dynamics simulation of silicon single crystal under Stillinger-Weber model and the main steps and processes of molecular dynamics simulation are introduced. The relationship between the coefficient of thermal expansion of silicon single crystal and the third-order force constants of two-body interaction and three-body interaction between atoms is derived by the method of lattice dynamics. The formula of lattice constant and thermal expansion coefficient of silicon single crystal is derived by using perturbation theory, and the physical mechanism of negative thermal expansion property of silicon single crystal at low temperature is explored. The results of lattice dynamics simulation, molecular dynamics simulation and experimental data of the thermal expansion properties of silicon single crystals are compared, and some conclusions are drawn: the negative thermal expansion properties of silicon single crystals do exist at low temperature. The fundamental reason for this property is that the third order force constant is positive.
【學(xué)位授予單位】：湖南師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN304.12

【參考文獻】

相關(guān)期刊論文 前1條

1 黃建平;胡詩一;;由熱學(xué)性質(zhì)獲取氬晶體原子間各階力常數(shù)[J];原子與分子物理學(xué)報;2014年06期

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本文編號：2121871