No abstract

Silicon dioxide (SiO 2 ) films deposited using Atomic Layer Deposition (ALD) technique from tris(dimethylamino)silane (TDMAS) and ozone as precursors on Si(100) surfaces at room temperature were investigated by infrared absorption spectroscopy with a multiple internal reflection geometry. TDMAS dissociatively adsorbs on OH sites of hydroxylated Si surfaces and ozone irradiation is effective to remove the hydroaminocarbon adsorbates introduced during the TDMAS adsorption. After the ozone treatment, treatments with H 2 O vapor at substrate temperatures around 160˚C allow regeneration of OH sites for the TDMAS adsorption. The TDMAS adsorption and the ozone treatment at room temperature followed by the H 2 O treatment at 160˚C enable the cyclic deposition of SiO 2 . I-V measurements performed on MOS capacitors with SiO 2 films reveal that the deposited films have breakdown electric fields in the range 3-11 MV/cm. These measurements together with C-V measurements indicate that the present ALD technique is suitable for the deposition of SiO 2 films for MOS capacitors.

We have studied SiO 2 ALD processes with precursors of tris(dimethylamino)silane (TDMAS) and ozone on Si(100) surfaces at room temperature by infrared absorption spectroscopy with a multiple internal reflection geometry. It was found that TDMAS dissociatively adsorbs on OH sites of hydroxyrated Si surfaces and ozone irradiation is effective to remove the hydroaminocarbon adsorbates introduced in the course of the TDMAS adsorption. Compensation of OH sites by a water vapor treatment after the ozone process is effective to sustain the cyclic SiO 2 deposition.

Quasi‐periodic variation of cosmic radio noise absorption (called CNA pulsation), measured by a fast‐response 30‐MHz riometer at Syowa Station in Antarctica (L ∼ 6), was examined. CNA pulsations with the period of 10–500 s are observed mostly during morning hours. Most of the CNA pulsations are associated with magnetic pulsations and quasi‐periodic (QP) VLF emissions. The examination of the relationships among CNA pulsation, QP emission, and magnetic pulsation, using the cross‐correlation analysis method, shows that some CNA pulsations with the period of 10–500 s are well related to magnetic pulsations and QP emissions. In these cases, CNA pulsations are more correlated with the D component of magnetic pulsations than with the H component. It is also shown that the phase of the CNA pulsation lags behind QP emissions by 60–120° independent of pulsation period.

No abstract