近年來由於積體電路技術日漸突破，元件尺寸越做越小，但功率的需求則越來越大。這些高功率輸出同時造成積體電路內散熱的問題，而薄膜微型熱電致冷器即是解決此問題的一種可行方法。將熱電材料做成薄膜的主因，除了可以將尺寸縮小化，使熱電致冷器在微小尺度上的應用具有較佳的整合性，亦可以配合積體電路封裝散熱的需求。本文利用多重耦合數值模擬軟體模擬薄膜熱電致冷器，考量實際製程陣列結構的致冷特性，分別利用熱擴散方程式與電動力學連續方程式，並帶入熱電效應重要定義，藉此建立統御方程式。另外由於材料結構性質的影響，導致在材料介面接合處產生聲子與電子熱非平衡現象，本文利用波茲曼方程式(Boltzmann equation)探討聲子與電子在材料溫度分佈。 本文首先主要探討單一摻雜型(Single type)熱電致冷器上電極設計對致冷溫度的影響，接著再探討以NiSi當PN模組(PN Module)薄膜熱電致冷器下電極時，觀察陣列結構的致冷特性。模擬結果發現，對Single type熱電致冷器致冷溫度較佳的電極寬度設計，其範圍會小於致冷器的致冷區域，且當電極的有效長度越長，對致冷溫度越不利。而以NiSi為PN Module薄膜微致冷器下電極進行陣列結構的模擬中，可以發現固定總致冷面積時，間隙介質熱傳導係數越高，對致冷器性能越不利。在聲子與電子熱非平衡模擬中，將熱電材料厚度縮小與增加電流時，會增加在材料介面處聲子與電子溫度不連續的區域，即所謂的非平衡區域(cooling length)。另外由於電子在介面處的邊界熱阻大於聲子的邊界熱阻，導致電子在介面溫度的變化範圍比聲子在介面溫度處的變化範圍來的大。上述本文的相關研究成果，可供未來設計微致冷器的參考依據。 With the rapid development of integrated circuit (IC) technology, the component size becomes smaller and smaller. Thermal management has become more and more important due to the requirement on high power output. Micro thermoelectric coolers (TE) provide a promising solution owing to the small size and high cooling power. The thin film TE cooler can not reduce its size for local hot spot cooling, but also have the capability of integration of IC fabrication. In the study, we perform numerical study on the thin film micro-TE coolers with difference configurations. Single type and PN module type TE coolers are considered. The governing equation is derived from the heat diffusion equation and the continuity equation for electric charge, coupled with the thermoelectric relation. The phonon and electron thermal non-equilibrium at the metal/thermoelectric materials interface is also discussed by solving the Boltzmann equation. First, we analyze cooling characteristics of the single type TE coolers different top contact geometry. Then we discuss TE cooler’s characteristics of thin film PN module arrays. The results shows that when the top contact width of a single type TE coolers is smaller than the width of the cooler, the better the cooling performance . The long effective length of the contact is found unfavorable to the cooling performance. In the PN module arrays, the thermal conductivity of the materials of array gaps can change the temperature. The higher cooling performance is obtained for lower themal conductivity of the gap media. Finlly, we considered the cooling length, which is defined as the distance for electrons and phonon non equilibriu,. When the TE materials thickness decreases or the current passing through the TE materials increases, the cooling length increases. It is due to the larger electron boundary resistance than the phonon boundary resistance.
