複晶矽電阻係數之研究

Abstract

單晶矽之電阻係數不會隨著形狀不同而改變，但是對於複晶矽而言，其電 阻係數卻會隨著薄膜厚度的變化而變化。因此，在本論文中我們研究了厚 度效應對於二氟化硼離子及砷離子佈植於低壓化學氣相沈積之複晶矽特性 的影響，包括了晶粒大小、電阻係數、有效自由載子濃度，以及移動率等 等，其摻雜濃度為 4E+20 和 1E+20 cm^-3 、厚度範圍為 25 至 200 nm 。 我們發現隨著厚度的變薄，電阻係數會變大，而有效載子濃度和移動 率會變小。除此之外，複晶矽薄膜經過電漿氫化、氧化、氫化／氧化之後 ，電阻係數會變大，尤其當厚度小於 50 nm 的時候。 With regard to single crystalline silicon, the resistivity is independent of geometry, while that of polycrystalline sil- icon thin film depends on the film thickness. The effects of film thickness on the grain size, resistivity, effective free carrier concentration, and mobility of BF2+ - doped or As+ - doped LPCVD polycrystalline silicon films with doping concen- tration 4E+20 cm^-3 and 1E+20 cm^-3 have been studied from 200 nm down to 25 nm. The resistivity increases, and the effective free carrier concentration and mobility decrease as the film thickness decreases. In addition, it is seen that the resis- tivity of polycrystalline silicon film increases after applly- ing hydrogen or oxygen hydrogen/oxygen plasma treatment, espe- cially for the film thickness less than 50 nm.