NASA Scientific and Technical Aerospace Reports

During the two-year duration of this program, we accomplished or made significant progress in three objectives for
specific integrated optical systems. The general technology focus was to develop practical methods for reducing the physical
dimensions of optical circuits through manipulation of the device geometry and refractive-index profile and develop several
new integrated optical devices on LiNbO3 devices. Our research on LiNbO3 has yielded a new low voltage E/O scanner,
techniques for poling thin crystal ion slicing (CIS) LiNbO3 films for integrated photonics applications, and several
silicon-on-insulator-based integrated-optic components having new and important functionality.
DTIC
Detection; Heterogeneity; Integrated Optics
20040111959 NASA Glenn Research Center, Cleveland, OH, USA
Measurement of Thin Film Integrated Passive Devices on SiC through 500 C
Schwartz, Zachary D.; Ponchak, George E.; Alterovitz, Samuel A.; Downey, Alan N.; Chevalier, Christine T.; [2004]; 4 pp.;
In English; IEEE International Microwave Symposium, 6-11 Jun. 2004, Fort Worth, TX, USA
Contract(s)/Grant(s): 22-714-70-18; Copyright; Avail: CASI; A01, Hardcopy
Wireless communication in jet engines and high temperature industrial applications requires FD integrated circuits
(RFICs) on wide bandgap semiconductors such as Silicon Carbide (SiC). In this paper, thin-film NiCr resistors, MIM
capacitors, and spiral inductors are fabricated on a high purity semi-insulating 4H-SiC substrate. The devices are
experimentally characterized through 50 GHz at temperatures of up to 500 C and the equivalent circuits are deembedded from
the measured data. It is shown that the NiCr resistors are stable within 10% to 300 C while the capacitors have a value stable
within 10% through 500 C.
Author
Jet Engines; Thin Films; Silicon Carbides; Semiconductors (Materials); Resistors; Inductors
20040111960 NASA Glenn Research Center, Cleveland, OH, USA
Measured Attenuation of Coplanar Waveguide on 6H, p-type SiC and High Purity Semi-Insulating 4H SiC through 800
K
Ponchak, George E.; Schwartz, Zachary D.; Alterovitz, Samuel A.; Downey, Alan N.; [2004]; 4 pp.; In English; IEEE MTT-S
International Microwave Symposium, 6-11 Jun. 2004, Fort Worth, TX, USA
Contract(s)/Grant(s): 22-714-07-09; No Copyright; Avail: CASI; A01, Hardcopy
Wireless sensors for high temperature applications such as oil drilling and mining, automobiles, and jet engine
performance monitoring require circuits built on wide bandgap semiconductors. In this paper, the characteristics of microwave
transmission lines on 4H-High Purity Semi-Insulating SiC and 6H, p-type SiC is presented as a function of temperature and
frequency. It is shown that the attenuation of 6H, p-type substrates is too high for microwave circuits, large leakage current
will flow through the substrate, and that unusual attenuation characteristics are due to trapping in the SiC. The 4H-HPSI SiC
is shown to have low attenuation and leakage currents over the entire temperature range.
Author
Waveguides; Planar Structures; Silicon Carbides
20040111997 NASA Langley Research Center, Hampton, VA, USA
Self-Nulling Eddy Current Probe for Surface and Subsurface Flaw Detection
Wincheski, B.; Fulton, J. P.; Nath, S.; Namkung, M.; Simpson, J. W.; [1994]; 7 pp.; In English; Original contains color
illustrations; No Copyright; Avail: CASI; A02, Hardcopy
An eddy current probe which provides a null-signal in the presence of unflawed material without the need for any
balancing circuitry has been developed at NASA Langley Research Center. Such a unique capability of the probe reduces
set-up time, eliminates tester configuration errors, and decreases instrumentation requirements. The probe is highly sensitive
to surface breaking fatigue cracks, and shows excellent resolution for the measurement of material thickness, including
material loss due to corrosion damage. The presence of flaws in the material under test causes an increase in the extremely
stable and reproducible output voltage of the probe. The design of the probe and some examples illustrating its flaw detection
capabilities are presented.
Author
Eddy Currents; Nondestructive Tests; Probes; Surface Defects
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