Browsing by Author "Lee, MD"

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Studies of nitride- and oxide-based materials as absorptive shifters for embedded attenuated phase-shifting mask in 193 nm
(1999)
Lin, CM
;
Chang, KW
;
Lee, MD
;
Loong, WA
;
應用化學系
Five materials which are PdSixOy CrAlxOy, SiNx, TiSixNy and TiSixOyNz as absorptive shifters for attenuated phase-shifting mask in 193 nm wavelength lithography are presented. PdSixOy films were deposited by dual e-gun evaporation. CrAlxOy, TiSixNy and TiSixOyNz films were formed by plasma sputtering and SiNx films were formed with LPCVD. All of these materials are shown to be capable of achieving 4%similar to 15% transmittance in 193 nm with thickness that produce a 180 degrees phase shift. Under BCl3:Cl-2=14:70 seem; chamber pressure 4 mtorr and RF power 1900W, the dry etching selectivity of TiSixNy over DQN positive resist and fused silica, were found to be 2:1 and 4.8:1, respectively. An embedded layer TiSixNy with 0.5 mu m line/space was successfully patterned.
Temperature dependence of magnetic properties in Ni-Mn-Ga shape memory alloys
(2004)
Lee, MD
;
Nong, NV
;
Thuy, NP
;
Yao, YD
;
Lee, SF
Due to exhibiting giant field-induce strain, the Ni2MnGa shape memory alloys are great interest for both scientific researches and industry applications. The non-stoichiometric Ni50Mn25+xGa25-x alloys with x varied from 1.5, 2.5 to 4 have been fabricated by arc-melting. Martensitic transformation temperature for structure transformation from tetragonal to cubic (T-M) was observed from the magnetization, electrical resistivity and X-ray diffraction studies as functions of temperature below 400 K. We found that T-M increases roughly from 280 K to 310K with increasing x from 1.5 to 4. However, the Curie transition (T-M) is roughly at 380 K for all the samples, it is insensitive to the variation of Mn/Ga ratio. The electrical resistivity data exhibit a deep near T-M and a slope change near T-C. We have experimentally demonstrated that the shape memory effect can be occurred at room temperature with a proper concentration variation of Mn and Ga. (C) 2004 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.