Aluminum oxide (Al2O3) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide (C12H30Al2O2), and water vapor (H2O) as the reactant at deposition temperatures ranging from 150 to 300 oC. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at 250 oC; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical ALD-Al2O3 process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/ cycle. The as-deposited ALD-Al2O3 film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at 1000 oC. The refractive index of the ALD-Al2O3 films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the ALD-Al2O3 films deposited at 250oC were stoichiometric, with no carbon impurity. The step coverage of the ALD-Al2O3 film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the Al/ALD-Al2O3/p-Si structure, the dielectric constant of the ALDAl2O3 films deposited at 250 oC was determined to be ~8.1, with a leakage current density on the order of 10−8 A/cm2 at 1 V.

We developed an Al sputtering process by varying the plasma power, process temperature, and film thickness. We observed an increase of hillock distribution and average diameter with increasing plasma power, process temperature, and film thickness. Since the roughness of a film increases with the increase of the distribution and average size of hillocks, the control of hillock formation is a key factor in the reduction of Al corrosion. We observed the lowest hillock formation at 30 W and 100 oC. This growth characteristic of sputtered Al thin films will be useful for the reduction of Al corrosion in the future of the electronic packaging field.

Changes in the surface morphology and light scattering of textured Al doped ZnO thin films on glasssubstrates prepared by rf magnetron sputtering were investigated. As-deposited ZnO:Al films show a hightransmittance of above 80% in the visible range and a low electrical resistivity of 4.5×10-4Ω·cm. The surfacemorphology of textured ZnO:Al films are closely dependent on the deposition parameters of heater temperature,working pressure, and etching time in the etching process. The optimized surface morphology with a cratershape is obtained at a heater temperature of 350oC, working pressure of 0.5 mtorr, and etching time of 45seconds. The optical properties of light transmittance, haze, and angular distribution function (ADF) aresignificantly affected by the resulting surface morphologies of textured films. The film surfaces, havinguniformly size-distributed craters, represent good light scattering properties of high haze and ADF values.Compared with commercial Asahi U (SnO2:F) substrates, the suitability of textured ZnO:Al films as frontelectrode material for amorphous silicon thin film solar cells is also estimated with respect to electrical andoptical properties.

첨가제로 Al2O3가 포함된 ZnO 소결체가 타깃을 이용하여 RF 마그네트론 스퍼터링법으로 Al이 첨가된 ZnO박막을 증착하고, 타깃에 첨가된 Al2O3</TEX>의 농도와 증착시 스퍼터링장치내의 기판위치에 따른 박막의 물성 변화를 고찰하였다. 타깃의 Al2O3 첨가농도가 2wt%인 경우에 비저항치 8 × 10-3 Ω-cm인 박막이 증차되었다. 또한 Al2O3</TEX>가 2wt%이상 첨가된 경우는 모든 Al이 박막내부에서 Zn를 치환하여 전자주게로의 역할을 하지 못하고, 오히려 치환되지 못한 Al원자의 중성 불순물 산란효과에 의해 박막의 비저항이 증가하였다. 타깃의 마모영역 위에서 증착된 Al을 첨가한 ZnO 박막은 그 영역 KR에서 증착된 박막보다 높은 비저항값을 나타냈으며, 이는 큰 에너지를 가지는 산소입자의 충돌에 기인한 것으로 여겨진다.