Manap, Abdul Haadi Abdul (2016) Molecular Mechanics Simulations Of Quartz Etching Process. Masters thesis, Universiti Sains Malaysia.
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Abstract
Thesis ini membentangkan hasil kajian tentang proses punaran secara fizikal menggunakan hentaman Argon ke atas substrat α-kuarza dan amorfus kuarza dengan menggunakan kaedah molekular mekanik. Walaupun kajian mendalam terhadap proses punaran ke atas kuarza sudah ada, namun kebanyakan daripadanya adalah secara eksperimen dan fokus kajian tersebut hanyalah pada hasil akhir proses tersebut. Terlalu sedikit kajian dijalankan yang menjurus kepada asas dan fundamental proses punaran. Dengan menggunakan kaedah Monte Carlo (MC) dan Molekular Dinamik (MD), para pengkaji dan ahli akademik mampu membina model proses punaran daripada awal hingga penghujung proses tersebut. Teknik ini membolehkan proses ini dikaji di tahap saiz sekecil molekul dan membantu pengkaji memahami teori asas dan fundamental proses punaran terhadap kuarza. Dua teknik penkomputeran digunakan untuk membina model proses punaran secara fizikal ke atas substrat kuarza. Teknik pertama berdasarkan statisik (teknik Monte Carlo) dan teknik kedua berdasarkan teknik ketentuan (Molekular Dinamik). Untuk teknik Monte Carlo, produk utama yang dicari adalah hasil percikan, Ys dan pembahagian tenaga pada atom yang terpercik. Selain itu, hubungan antara tenaga tujahan, Ei, sudut tujahan, θi kepada hasil akhir juga dibincangkan. Berdasarkan teknik ini, pada sudut tujahan, θi =70⁰ dengan sebarang tenaga tujahan, Ei,hasil percikan, Ys yang dihasilkan adalah maximum. Teknik molecular dinamik pula melaporkan kesan terhadap punaran secara terpilih, kesan suhu substrat,Ts dan kesan tenaga tujahan, Ei terhadap hasil pemercikan atom dan seterusnya menghubungkan hasil pemercikan atom dengan sifat-sifat subtrak. Objektif utama projek ini adalah untuk mengguna kaedah pengkomputeran bagi membina model proses punaran di skala dalam molekul. Dua jenis substrat yang berlainan (α-kuarza dan amorfus kuarza) digunakan dan substrat tersebut melalui proses hentaman Argon dengan tenaga tujahan, Ei suhu substrat, Ts berlainan secara berkala. Model komputer punaran kuarza menggunakan Potensi Morse dan Potensi COMB (Charged Optimized Many-Body) sebagai potensi antara atom. Berdasarkan kajian yang telah dibuat, α-kuarza menghasilkan pemercikan atom lebih tinggi daripada amorfus kuarza dengan menggunakan mana-mana tenaga tujahan, Ei dan suhu substrak, Ts. α-kuarza juga menghasilkan pemercikan atom yang lebih stoikiometrik berbanding amorfus kuarza. Ini desebabkan untuk α-kuarza produk pemercikan dalam bentuk SiO2 dan amorfus kuarza dalam bentuk atom. Tenaga tujuhan, Ei menghasilan impak yang lebih besar kepada hasil pemercikan atom berbanding suhu substrak, Ts. Di dalam kajian ini, model pengkomputeran untuk proses punaran berjaya didemonstrasikan dengan mengunakan kaedah Monte Carlo (MC) dan Molekular Dinamik (MD). Beberapa faktor yang memberi kesan ke atas punaran telah pun dikaji dan pemahamam terhadap proses punaran di skala molekul berjaya ditambah. Hasil kajian dari tesis ini berpotensi untuk digunakan di dalam proses pencorakan untuk fabrikasi nano 2D dan 3D. ________________________________________________________________________________________________________________________ In this thesis, the physical etching of argon bombardment onto α-quartz and amorphous quartz substrates were studied and investigated using molecular mechanics methods. Although there are extensive studies on quartz etching, larger numbers of the research are experimental and the studies focus on the process outcomes rather than the fundamental study of the process. Molecular mechanics methods such as Monte Carlo (MC) method and Molecular Dynamics (MD) method enables researchers in building the model from ground up to the physical etching process. This kind of bottom-up design allows us to study the process in molecular level and help researcher grasp the fundamental theory of the process. Two computational methods have been employed in order to study quartz etching process. The first method are based on statistical approach i.e Monte Carlo and the second method is based on deterministic approach i.e Molecular Dynamics. In Monte Carlo method, the main interest of the simulations is sputtering yield, Ys and energy distribution of sputtered atoms. The relationship of incident energy, Ei , and incident angle θi to the interested subjects will also been investigated and discussed. It was found that at incident angle θi =70⁰ at any incident energy, Ei, the sputtering yield, Ys is maximum. Molecular Dynamics method reported the effect of etching selectivity, the effect of substrate temperature, Ts, and the effect of incident energy, Ei to the sputtering yield and ultimately corroborates the factor and sputtering yield with the properties of the substrate. The main objective of this project is to use computational method (i.e Molecular Dynamics) to model the process at the scale of molecular level. Two difference substrates (amorphous and α-quartz) are subjected to a range of incident energy. Ei and temperature, Ts and the sputtering yield were studied. Morse potential and Second Generation Charge-Optimized Many Body (COMB) potentials were utilised as the inter-atomic potential. α-quartz shows higher sputtering yield as compared to amorphous quartz at any given incident energy, Ei and substrate temperature, Ts. α-quartz has also produced more stoichiometric yield compared to amorphous quartz. This is because for α quartz, the sputtered product are in mostly the form of SiO2 molecule while amorphous substrate the sputtered product in the form of atom. Incident enery, Ei gave significant increase in the sputtering yield compared to temperature, Ts. In this thesis, the computational model of physical etching on quartz has been demonstrated using the Monte Carlo (MC) method and Molecular Dynamics (MD) method. Several factors are studied and better understandings of the process in molecular level have been achieved. The results of this study could be applied in 2D and 3D patterning used in lithography technique.
| Item Type: | Thesis (Masters) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=3087 |
| Subjects: | T Technology T Technology > TJ Mechanical engineering and machinery > TJ181-210 Mechanical movements |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Mekanikal (School of Mechanical Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 30 Aug 2018 04:27 |
| Last Modified: | 30 Aug 2018 04:27 |
| URI: | http://eprints.usm.my/id/eprint/41604 |
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