| 摘要: | 本論文研究主題將以離子佈植的方法將雜質摻雜於矽基板與氧化鋅基板，探討熱製程對雜質於矽基板產生的應力保存影響與多重離子佈植形成P型氧化鋅薄膜。
由於利用非平衡方式的離子佈植來突破碳離子在矽基板中的平衡溶解度以形成足夠大的應力於假晶型的碳矽合金，故應力如何保存於此雅穩態將會是應力矽基板被應用的關鍵。從高解析度X光繞射儀得知高濃度5*1014 ions/cm2磷摻雜(CP3)的樣品應力大量消失於高溫的退火後，但其他無磷摻雜(C only)或較低濃度磷摻雜(CP1 and CP2)的樣品應力幾乎完整保存，雖然可以確定高濃度磷摻雜會影響應力於熱製程下保存，但從高解析X光繞射儀的模擬可以發現只有深層的應力釋放和摻雜磷濃度有正相關關係而表面的應力釋放卻不全然如此。在樣品表面，只有CP3樣品有著大量的應力釋放消逝而其他樣品的應力卻只有些許應力改變，此現象說明了除了摻雜的磷外樣品表面還有另一個因素影響著應力的保存。從傅氏轉換紅外線光譜可以發現晶格位置上的碳含量(607cm-1)、過渡帶的碳矽化合物(750cm-1)及β-SiC(810cm-1)的特徵訊號皆沒有太大變化，反倒是樣品表面的氧化物與應力釋放消逝有著相同趨勢，在比較各樣品的含氧量發現高濃度的磷摻雜會促使表面氧化且增加氧往樣品深處擴散，而在熱退火製程前的氫氟酸去除CP3之表面氧化層對於應力穩定保存有著顯著幫助。另外，所有經過退火製程的樣品都因電阻值過大而無法進行霍爾量測。基於高解析X光繞射儀、傅氏紅外線光譜和霍爾量測結果，我們不僅可以確定摻雜的磷和退火形成的氧是應力釋放消逝的兩大因素，且在於不超800的退火環境下之所以會有應力釋放消逝是因為晶格位置上的碳有著良好的吸附間隙雜質作用並以體積補償的方式達到應力釋放消逝的機制。最後我們提出一改善的製作流程，並希望能以此流程模組可以製作應力可以保存於矽基板以被N型場效電晶體所應用。
由於授予缺陷的形成能量較低，所以成長的氧化鋅基板都會是天生N型導電性，但若想要突破發光效率的限制，P型氧化鋅的形成來製作氧化鋅同質元件是一必要的條件。在氧化鋅的研究中我們利用特定比例的多重離子佈植來製作P型氧化鋅薄膜，從單元素氮的離子佈植(N sample)只能形成較微N型氧化鋅薄膜而無法有電特性上的轉變，但可以藉由比例為四的氮磷雙重離子佈植(NP sample)來使的原本N型的氧化鋅薄膜變成P型氧化鋅薄膜，且額外的氧離子佈植(NPO sample)不僅可以獲得具有2.34*1019cm-3電洞濃度的最佳導電性P型氧化鋅薄膜且同時也增加了離子佈植後形成P型氧化鋅薄膜的活化溫度範圍，利用P型氧化鋅薄膜與N型氧化鋅薄膜所形成的同質元件可以發現電晶體有著微整流的效果更加確定P型氧化鋅形成於多重離子佈植的樣品。從高解析X光繞射儀和X光光電子能譜的分析，我們可以發現在氮的1S軌域除了有氮原子佔據氧晶格位置的特徵訊號(~397eV)外，氮分子佔據氧的晶格位置的特徵訊號(~399eV)的產生說明從高解析X光繞射儀觀察到的晶格常數會變大是因為相較於其他可能結構較大的氮分子佔據氧的晶格位置而導致整體晶格常數變大。P型氧化鋅是因為離子佈植的磷佔據鋅的晶格位置與氮佔據了氧的晶格位置同時發生並形成複合物的受子缺陷而形成，因此在固定比例的氮磷離子佈植下，增加複合受子缺陷的型成促使P型氧化鋅薄膜生成，且額外的氧離子佈植減少了氧化鋅薄膜表面的氧空缺晶格的施體缺陷，因此可以在較廣的活化溫度範圍內得到較穩定且高電子濃度的P型氧化鋅薄膜。
;In this thesis, impurities doped in silicon and ZnO substrate via ion implantation method are conducted for strain stability retention under thermal treatment in strained silicon and P-type ZnO thin films formation with cocktail implantation method.
Since non-equilibrium method, ion implantation, is employed for exceeding the equilibrium solubility and generating larger enough strain in pseudomorphically silicon carbon alloy, strain stability retention in this metastable state in silicon plays a key role for further application. With High resolution X-ray diffractometer, it is found that significant strain relaxation occurs in the highly phosphorus doped concentration, 5*1014 ions/cm2, sample (CP3) under post-annealing thermal treatment, but almost full(adv.) strain stability retains in carbon only (C only) and in lower phosphorus doped concentration samples (CP1 and CP2) under same post-annealing thermal treatment. Even though strain stability retention is affected by the highest phosphorus doped concentration, it is found from dynamics simulation that strain relaxation is proportional to phosphorus doped concentration in only bulk region, not effectual in surface region. In surface region, only significant strain relaxation appears in CP3 sample and little strain relaxation arises in the rest of samples, indicating there is another strain stability retention factor in the surface. From Fourier transform infrared spectroscopy, the characteristic peaks of substitutional carbon at ~607cm-1, transition Si-C at ~705cm-1, and β-SiC at ~810cm-1 do not apparently change. In contrast, the oxygen-related peak area evolution trend is in correspondence with strain relaxation evolution in surface region. Furthermore, it is observed that the highest phosphorus doped concentration promotes the surface oxidation and facilitates oxygen diffused into bulk from SIMS and HF pretreatment prior to post-annealing facilitates the strain stability retention via removed surface oxide. From Hall measurement, only the electrical properties can be obtained in as-grown samples, but the sheet resistance becomes so high that it is overflow for all post-annealing samples.
Based on the results of high resolution X-ray diffractometer, Fourier transform infrared spectroscopy and Hall measurement, it is determined that implanted phosphorus and oxidation via post-annealing are two main factors for strain relaxation and that the volume compensation with good gettering ability of substitutional carbon is the only probably strain relaxation mechanism. Finally, new process flow is proposed for strain stability retention in phosphorus doped SiC alloy for N-MOSFETs fabrication.
Native N-type ZnO substrate is always obtained caused by the formation of donor-like defects, which have lower formation energy, during ZnO growth, but the formation of P-type ZnO substrate is required for overcoming the efficiency limitation of light emitted by ZnO homojunction. Specific ion implantation dosage is utilized for P-type ZnO thin films formation through cocktail implantation method. It is found that mono-doped ZnO by nitrogen implantation results in slight N-type conductivity under thermal activation. Dual-doped ZnO thin film with a N:P ion implantation dose ratio of 4:1 is found to be P-type under certain thermal activation conditions. Higher hole concentration (2.34*1019cm-3) can be achieved in dual-doped ZnO co-implanted with additional oxygen under a wider thermal activation window. It is more convincing P-type ZnO formation by observing a slight rectifying behavior with P-ZnO: (NPO at 600℃)/ N-ZnO (as-grown) homojunction. From high resolution X-ray diffractometer and X-ray photoelectron spectroscopy, we can find that substitutional nitrogen, NO, and substitutional nitrogen molecular, (N2)O, in N1S spetrum are at ~397eV and ~399eV respectively. It elucidates the increasement of lattice constant following the nitrogen implantation since nitrogen molecular exists and dominates the lattice constant. Moreover, the observed P-type conductivities are results of the promoted formation of PZn-4NO complex acceptor defects via the concurrent substitutional of nitrogen at oxygen sites and phosphorus at zinc sites. The enhanced solubility and the stability of acceptor defects in oxygen co-implanted N:P dual-doped ZnO film are related to the reduction of oxygen vacancy defects at the surface. It demonstrates the prospect of the formation of stable P-type ZnO thin film through cocktail implantation with specific implantation dosage. |
