Properties of intrinsic gettering of Fe were studied by measuring Fe-B complex concentration and interstitial Fe concentration in a denuded zone after isochronal or isothermal annealing followed by quenching using deep level transient spectroscopy. We calculated the Fe concentration as the Fe-B complex concentration plus the interstitial Fe concentration. Silicon wafers were contaminated with a surface Fe concentration of 4.2×1011 to 3.2×1013 cm−2 to show the relation between Fe concentration in the wafer and the temperature at which gettering occurs. Supersaturation of Fe impurities was found necessary for intrinsic gettering of Fe in the contamination range of 4.0×1012 to 3.5×1014 cm−3. Therefore, the gettering temperature is lower for low-level Fe contamination than for high-level contamination. The reduction of Fe concentration saturated with annealing time, which shows that the oxygen precipitates in the bulk defect region do not work as an infinite gettering sink. We found that the saturated Fe concentration follows a simple Arrhenius relationship, so that gettering stops at the thermal equilibrium concentration. We think that in intrinsic gettering, Fe precipitates preferentially in the bulk defect region when the Fe impurities supersaturate with decreasing temperature.

A stress-operated memory device consisting of an ellipsoidal magnetic particle array and an electrostrictive grid is proposed. In the device, the magnetic state of the particle can be controlled only by the magnetostriction effect. Each particle is located at the intersection of the grid and has an in-plane uniaxial anisotropy. A pair of electric contacts is connected to the end of each wire. In the writing process, the driving voltages are simultaneously applied to two pairs of the selected contacts. This allows to apply a local electric field whose direction and amplitude can be regulated by varying the voltage intensity and polarity. The exerting stress on the magnetic particle results in the linear magnetostriction and hence an additional anisotropy energy in the particle. The in-plane total energy minimum, corresponding to the magnetization direction, follows the local electric field. Consequently the magnetization of the single magnetic particle located at the intersection can therefore be selectively switched.

Thin oxides grown on silicon substrate in which Cu+ ions had been implanted before oxidation were studied by transmission electron microscope (TEM) and scanning TEM imaging methods. Cu precipitates, stacking faults, and dislocations appeared at the SiO2/Si interface on the degraded specimens. The Cu precipitates reduce the breakdown strength by local thinning of the oxide thickness. Stacking faults and dislocations, however, do not reduce the breakdown strength.

A reliable method of controlling iron impurities on the silicon wafer surface at low levels has been developed by using an iron-contaminated HNO3 solution. Iron ions are thought to react with the silicon native oxide to form an Fe(III)-O complex in proportion to the iron concentration in the solution. Using this method, we have quantitatively investigated the influence of iron impurities on metal-oxide-semiconductor device characteristics. The drastic degradation of generation lifetime, surface generation velocity, and dielectric breakdown strength of SiO2 have been observed above the surface iron concentration of 1×1012, 5×1012, and 1×1013 cm−2, respectively.

The behavior of metal impurities (Cu, Fe, Cr, and Ni) near the SiO2‐normalSi interface during dry O2 and O2/normalHCl oxidation was studied by means of defect etching and secondary ion mass spectroscopy methods using intentionally metal‐contaminated silicon wafers. Redistribution of metal impurities resulting from a thermal oxidation is different for each metal. Copper diffused into the silicon, showing concentration peaks 0.3–1.2 μm from the interface, and tended to be rejected by the silicon dioxide. Iron accumulated at the interface, while chromium tended to accumulate in the oxide having a lower concentration in silicon. Gettering ability using O2/normalHCl oxidations was excellent for copper, but poor for iron and chromium impurities. Copper and iron impurities precipitate in the silicon near the interface, but chromium and nickel impurities do not.