J. E. Mee

Magnetic oxide films

Polycrystalline and epitaxial magnetic oxide films have been fabricated by several investigators. This paper deals predominantly with epitaxial films grown by chemical vapor deposition. The majority of the discussion is concerned with substrates, the deposition process, and film characterization. Where possible, comparisons are made with bulk crystals and with films produced by other fabrication techniques.

A stress model for heteroepitaxial magnetic oxide films grown by chemical vapor deposition

Abstract A simple physical model is presented which predicts the sign and magnitude of stress in heteroepitaxial films. The model explains experimental observations of ferromagnetic resonance, domain structure, and crazing in magnetic oxide films grown by chemical vapor deposition (CVD) on non-magnetic substrates. It provides a means of predicting and developing compatible film-substrate combinations for epitaxial bubble domain materials utilizing a stress-induced uniaxial magnetic anisotropy. A basic result of the model, the conditions under which films can be grown in compression, has been verified experimentally for CVD iron garnets.

Mobile Cylindrical Magnetic Domains in Epitaxial Garnet Films

The properties of cylindrical domains in wafers of bulk single crystals of various magnetic oxides have been extensively studied and described in recent months. Mobile cylindrical domains have been produced in single‐crystal thin films of gallium‐substituted yttrium iron garnet. The deposits are formed by chemical vapor deposition onto nonmagnetic garnet substrates greater than 1 cm2 in area. A model of magnetic anisotropy in epitaxial films is proposed and shown to be in good agreement with experimental domain observations. In a typical sample, a domain diameter of 8 μ is observed in a 6‐μ‐thick film at a bias field of 25 Oe. From the domain translational velocity of 5600 cm/sec, a cylindrical domain mobility of 1500 cm/sec Oe has been calculated. A fractional change in cylindrical domain diameter of −0.07%/°K has been measured at 300°K. Annealing at 1570°K for several hours did not alter the Neel temperature or the optical transmission spectrum.

Heteroepitaxial Si films on yttria‐stabilized, cubic zirconia substrates

Epitaxial single‐crystal growth of Si films has been achieved on the (100), (110), and (111) planes of yttria‐stabilized, cubic zirconia single crystals. The Si films were grown by the pyrolysis of SiH4 at temperatures in the range 950–1075 °C and at deposition rates of 0.08–1.2 μm/min. The structural and electrical properties of the Si films have been determined by Rutherford backscattering and channeling, x‐ray diffraction, and Hall effect measurements. Several 0.4–0.5‐μm‐thick (100) and (110) Si films on cubic zirconia were found to be of higher crystal quality than commercial (100) Si‐on‐sapphire films of similar thickness.

Ferromagnetic Resonance in Epitaxial Garnet Thin Films

The chemical vapor deposition process for growing epitaxial yttrium iron garnet (YIG) has matured to the point where films of varying geometry and thickness from ½ to as great as 40 μ can be readily grown on several orientations of gadolinium gallium garnet, yttrium aluminum garnet, and YIG, itself. As a measure of the quality of the films, line widths (at 9.4 GHz and room temperature) as small as 0.6 and 1.4 Oe were obtained in samples with substrates removed and intact, respectively, without a major effort toward improvement. Magnetostatic modes, exchange modes, and ferromagnetic normal modes having comparable exchange and demagnetization energies were observed in these films and in thin bulk disks and were explained in detail by a new theory which applies not only to films, but also to samples of arbitrary shape and size, and includes the effects of exchange and demagnetization energies. The frequencies of the general normal modes were calculated by casting the linearized equation of motion of the magn...

Ferromagnetic resonance properties of LPE YIG films

This is the first report of the ferromagnetic resonance properties of thin single-crystal YIG films grown by liquid phase epitaxy techniques (LPE). The resonance linewidths of photoetched disks are close to that of bulk YIG for both parallel and perpendicular resonance without any annealing of the films. A new type of surface spin wave, localized at the air-film interface, is shown to exist in perpendicular resonance. The boundary conditions necessary for this surface spin wave to exist are produced either by SiO 2 sputtering or ion implantation.

Electrical characterisation of ion-implanted silicon-on-sapphire

Electrical parameters of carrier transport in SOS films were investigated by measuring gate capacitance at frequencies ranging from 1kHz to 10MHz, conductance both in the linear region and in the saturation region and Hall effect as a function of gate bias voltage. The results show that the mobility decreases almost linearly with increasing distance from the Si/SiO2 interface. Similar characteristics were obtained for the carrier concentration profile. The magnitudes drop more than 200 percent from the Si/SiO2 interface to about 0.2μm deep in the Si film. This experimental result is very different from the data predicted by SUPREM. Spreading resistance profiles measured on the same n-type SOS film. after wafer processing show increasing resistivity with increasing distance from the Si surface. The doping profile calculated from spreading resistance data by using the mobility data obtained from the gated Hall effect measurements also indicates that the n-type carrier concentration decreases toward the Si/sapphire interface. The discrepancy between experimental data and the carrier concentration profile predicted by SUPREM can be explained by the existence of deep-level acceptor traps that are evident from Hall effect measurements made on a lightly boron-implanted SOS sample. The temperature dependence of the free carrier concentration shows an activation energy close to 0.31 eV. Mobility and carrier concentration measured by different techniques is discussed.

Channel doping profile of silicon‐on‐sapphire transistors

Dopant profiles of low‐dose channel implant in silicon‐on‐sapphire (SOS) field‐effect transistors are investigated by comparing results from various techniques, including theoretical calculation by the Stanford University integrated‐circuit process simulation program (suprem) and experimental measurements by secondary ion mass spectrometry (SIMS), capacitance‐voltage (C‐V), spreading resistance and metal‐oxide‐semiconductor Hall effect. It is shown that, for both phosphorus‐ and boron‐implanted SOS films having constant doping profile at a level close to 1×1016 cm−3, as predicted by suprem and measured by SIMS, the charge density measured by C‐V technique and free carrier concentration obtained from spreading resistance technique decrease with increasing distance from the Si surface. For SOS films implanted to a level greater than 1× 1017 cm−3 boron, the dopant profile obtained by SIMS analysis coincides with the charge density profile, measured by C‐V technique, and the free carrier concentration profile...

Characteristics of epitaxial garnets grown by CVD using single metal alloy source

Single metal alloys have been explored as the cation source in the chemical vapor deposition (CVD) of iron garnets. Growth of good quality single crystal garnet films containing as many as five different cations has been achieved over a wide range of deposition conditions. The relationship of film composition to alloy compositions and deposition conditions has been determined for several materials. By proper choice of the alloy composition and the deposition conditions, uncrazed deposits were grown on