Ion Implantation Patterning Research Articles

Nanopatterning by ion implantation through nanoporous alumina masks

The important problem of how to generate lateral order for ion implantation patterning of substrates is solved by using a nanoporous anodic alumina membrane as a mask. Co and Pt implantation is used at two implantation doses. In order to observe the achieved implantation zones free from artifacts, electron transparent thin nitride and oxide films are used as substrates, which allows the quality of pattern transfer from the mask to the thin film to be assessed by plan-view transmission electron microscopy. Characteristic density variations of implanted elements across projected pore-regions of the mask, such as ring and dome shapes, and corresponding variation of cluster size are discussed, and therefore the method also serves as a suitable test bed for ion beam focusing studies by cylindrical or conical pores.

Microwave characterization of coplanar waveguide transmission lines fabricated by ion implantation patterning of YBa/sub 2/Cu/sub 3/O/sub 7-δ/

We report on the application of Si and Al ion-implantation patterning to the fabrication of low-loss microwave transmission lines in high-temperature superconductor (HTS) thin films. Using this technique, we have fabricated coplanar waveguide (CPW) transmission lines in YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) thin films deposited on LaAlO/sub 3/ substrates. We have used both resonant and broadband measurements in order to characterize the performance of the resulting transmission line structures. For the broadband measurements, on-wafer calibrations were used to obtain accurate S-parameters and transmission line propagation constants up to 25 GHz. The propagation constants of the ion-implanted transmission lines do not differ significantly from those of lines patterned using conventional ion milling over the frequency range studied, with a value for the attenuation constant of approximately 0.03-0.04 dB/cm at 50 K and 10 GHz. The relatively low losses of the ion-implanted devices demonstrate the effectiveness of this method of patterning for HTS microwave device fabrication.

Planar microwave devices fabricated by ion-implantation patterning of high-temperature superconductors

We have applied ion-implantation inhibit patterning as a new method of fabricating low-loss microwave transmission lines in high-temperature superconductor thin films. To determine the effectiveness of this technique, we fabricated coplanar waveguide transmission lines in YBa2Cu3O7−δ thin films that had been deposited on LaAlO3 substrates using pulsed laser deposition. Microwave characterizations of these lines are compared to a reference line fabricated with conventional ion milling. At 76 K and 12 GHz, the attenuation constants of the ion-implanted transmission lines are approximated 0.02 dB/mm, and the overall loss response is indistinguishable from that of the ion-milled device.

Charged Wall Behavior Observed by Bubble Run-Out Method

A new potential well measurement method, utilizing bubble run-out phenomena, is discussed, with emphasis on its application in observing charged wall behavior, as well as in measuring the potential well depth itself. The method is applied to bubbles in ion implanted propagation patterns on 1 μm bubble garnet films with different magnetostriction constants. Bubble run-out directions are found to be reflected by the strength of stress relaxation-induced magnetic anisotropies along ion-implantation pattern edges. The charged wall length and its stray field distribution were also estimated using this method. It is concluded that this method is one of the most useful tools available for operation error mode analysis in ion-implanted bubble device development.

バブルランアウト法を用いたチャージドウォールの評価

A new potential well measurement method, using the bubble run-out phenomena, has been discussed for its application to observe charged wall behavior as well as to measure potential well depth itself. The method is applied to bubbles in ion-implanted propagation patterns on 1 μm bubble garnet films with different magnetostriction constants. Bubble run-out directions are found to be reflected by the strength of stress relaxation induced magnetic anistropies along ion-implantation pattern edges. Charged wall length and its stray field distribution are also estimated by the method. It is concluded that this method is one of the most useful tools for operation error mode analysis in ion-implantion bubble device development.

Characterization of self-aligned transfer gates for 1µm bubble contiguous-disk devices

Self-aligned transfer gates for contiguous disk bubble devices have been characterized at 200kHz. These devices require a single masking level to define both the current control conductors and ion-implantation pattern. Switch operation relies on a unipolar current pulse in the major loop which stripes the bubble between major and minor loops along a bridging charged-wall; directionality is provided by the crystalline symmetry effects in the drive layer. Representative transfer pulse parameters for a 28 Oe (8%) overlapping bias field margin are: (i) transfer-in, amplitude 115 mA ±25%, width 0.1μs ±15% and phase margin \pm16\deg . (ii) transfer-out, amplitude 160 mA ±9%, width 0.88μs ±10% and phase margin \pm10\deg . The transfer pulse requirements are discussed in terms of the behaviour of the charged-walls in the garnet drive layer.