Soft X-ray Absorption and Photoemission Studies of Ferromagnetic Mn-Implanted 3CC-SiC

We have performed x-ray photoemission spectroscopy (XPS), x-ray absorption spectroscopy (XAS), and resonant photoemission spectroscopy (RPES) measurements of Mn-implanted 3$C$-SiC (3$C$-SiC:Mn) and carbon-incorporated Mn$_{5}$Si$_{2}$ (Mn$_{5}$Si$_{2}$:C). The Mn 2$p$ core-level XPS and XAS spectra of 3$C$-SiC:Mn and Mn$_{5}$Si$_{2}$:C were similar to each other and showed "intermediate" behaviors between the localized and itinerant Mn 3$d$ states. The intensity at the Fermi level was found to be suppressed in 3$C$-SiC:Mn compared with Mn$_{5}$Si$_{2}$:C. These observations are consistent with the formation of Mn$_{5}$Si$_{2}$:C clusters in the 3$C$-SiC host, as observed in a recent transmission electron microscopy study.Comment: 4 pages, 3 figure

Cd1-xMnxTe/Cd1-yMgyTe ヘンチョウ ドープ ヘテロ コウゾウ ノ サクセイ ト 2ジゲン デンシケイ ノ キョウジバ ブッセイ

筑波大学博士 (工学) 学位論文・平成14年3月25日授与 (甲第2879号

Reactive ion etching of transition-metal alloys

For production of advanced spin-electronic devices, such as a magnetic random access memory with the higher-density memory cell, a reactive ion etching (RIE) process of transition metal alloys is the indispensable component of development, while no transition-metal compounds with the relatively high vapor pressure have been founded so far. Here, we show the RIE process of a NiFe thin film by using CH4:O2:NH3 discharge. The RIE process was designed by ab initio calculations, and the present result is the first successful demonstration of the chemical effect in the RIE process for transition-metal alloys. The relative etching ratio of NiFe against Ti as the metal mask was decreased by substituting CH4 with CHF3

Diminution of the activity of B atoms by H-induced defects in H

Diborane and hydrogen ions were co-implanted into silicon using an implanter without an ion analyzer. The samples were annealed at 1000 °C for 30 min in argon atmosphere. Regions containing carriers became narrower with an increasing fraction of H2 gas in the source mixed gas: for example, carriers were limited only in a narrow region from the surface to $0.3\;\mu$m on silicon implanted with a mixed gas of 57% H2–43% B2H6. The width of the region containing carriers was approximately double that ($\sim 0.6\;\mu$m) on B-implanted silicon. On the other hand, the width of the region containing B atoms on the H2 and B2H6 co-implanted silicon were slightly narrower than that on B-implanted silicon. The region containing inactivated B atoms had a large number of defects and small crystallites

First-principles calculations-based model for the reactive ion etching of metal oxide surfaces

A model for the RIE process design of metal oxide surfaces based on density functional theory-based total energy calculations has been developed. Cluster and periodic systems were employed in order to develop the model and hence gain a deeper understanding of the process mechanisms on an atomic scale. In the present study, FeO was used for the cluster system, and NiO for the periodic system as metal oxide surfaces. Possible gas combinations and by-products were studied with the aim of producing a more efficient and effective RIE process for metal oxide thin films. This study can be considered as fundamental groundwork required for the understanding of the reactivity in the etching of metal oxide surfaces and a means of decreasing the processing period of RIE for metal oxide thin films by optimum selection of gas combinations with a knowledge of their probable by-products

Design of reactive ion etching process based on ab-initio calculation - The first step-

We propose an intricate method of Reactive Ion Etching (RIE) process design for transition-metal (TM) materials using ab-initio calculations. The TM materials are inert in dry etching processes since volatile etching by-products cannot be formed easily. However, to achieve new high-performance memories based on the TM materials, a selective dry etching technique such as RIE is eagerly required instead of the conventional ion milling method. In this work, we would like to introduce our scenario of the RIE design for TM materials using the results of CoFe as an example