Focused ion beam direct deposition

and its applications

4. Applications of direct deposited films

Relationship between merits and applications

Surface acoustic wave device

Principle of surface acoustic wave (SAW) devices

Expected features of direct deposited interdigital transducers (IDT)

1.High power capability

2.Flexible design

Experiment

Fabrication of bandpass filter

Substrate : LiNbO3 (64°YX)

IDT : direct deposited Au,Cu,Al

Pictures of SAW sample

Before deposition of IDT

After deposition of IDT

Measured characteristics of fabricated sample

(direct deposited Al IDT 41pairs/41pairs, 4.8 μm period)

Measured characteristics of referenced sample

(Al IDT 81pairs/81 pairs, 4.8 μm period)

Measured characteristics of fabricated sample

(direct deposited Au IDT 41pairs/41pairs, 4 μm period)

Lower insertion loss was observed.

Superconducting quantum interference device(SQUID)

Weak link fabrication of Quasi-Planar-Josephson-Junction

Expected feature of direct deposited weak link :

Controllability and reproducibility of critical current

Photograph of Josephson Junctions

I-V curve of fabricated Josephson Junction

H-V curve of fabricated DC-SQUID

Diagram of DC-SQUID circuit

Noise characteristics of fabricated DC-SQUID

Performance of DC-SQUID was comparable to ordinary tunnel junction DC-SQUID.

Co/Cu multilayer

Fabrication of Co/Cu multilayer

with 108 eV Co2+ beam and 54 eV Cu+ beam

(Cu-Co-Nb-Au alloy ion source)

Expected features :

1.Magnetic/nonmagnetic multilayer

2.Controllability of thickness

3.Giant magnetoresistance (GMR) effect

Experiment:

1.Fabricate Co/Cu multilayer

108 eV Co2+ beam and 54 eV Cu+ beam

14X76 μm2

2.0 nm Co 12 layers and 1.3 - 2.2 nm Cu 11 layers

2.Form probe electrodes

54 eV Au+ beam

Photograph of fabricated sample

Measured MR ratio (dR/R) as a function of applied magnetic fields

Measured MR ratio (dR/R) as a function of Cu layer thickness

GMR effect was observed.

Precise controllability of thickness

Probing on small crystal

Restrictions on applications

1.Sample size

Deposition time by 10 nA beam

100 μm x 100 μm x 0.1 μm : 17 minutes

10 mm x 10 mm x 0.1 μm : 116 days

2.Mass production

Processing time for 1 sample

FIBDD : ~1/2 day

Photo-lithographic process : 1 week ~ 1 month

Processing time for 1,000,000 samples

FIBDD : > machine life

Photo-lithographic process : 1 week ~ 1 month

Conclusions

We developed some applications of FIBDD and proved that FIBDD is a useful tool for research and development.