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Full-Text Articles in Physics
Deep Traps In Algan/Gan Heterostructures Studied By Deep Level Transient Spectroscopy: Effect Of Carbon Concentration In Gan Buffer Layers, Z-Q. Fang, B. Claflin, David C. Look, D. S. Green, R. Vetury
Deep Traps In Algan/Gan Heterostructures Studied By Deep Level Transient Spectroscopy: Effect Of Carbon Concentration In Gan Buffer Layers, Z-Q. Fang, B. Claflin, David C. Look, D. S. Green, R. Vetury
Physics Faculty Publications
Electrical properties, including leakage currents, threshold voltages, and deep traps, of AlGaN/GaN heterostructure wafers with different concentrations of carbon in the GaN buffer layer, have been investigated by temperature dependent current-voltage and capacitance-voltage measurements and deep level transient spectroscopy (DLTS), using Schottky barrier diodes (SBDs). It is found that (i) SBDs fabricated on the wafers with GaN buffer layers containing a low concentration of carbon (low-[C] SBD) or a high concentration of carbon (high-[C] SBD) have similar low leakage currents even at 500 K; and (ii) the low-[C] SBD exhibits a larger (negative) threshold voltage than the high-[C] SBD. Detailed …
Electron-Irradiation-Induced Deep Level In N-Type Gan, Z-Q. Fang, Joseph W. Hemsky, David C. Look, M. P. Mack
Electron-Irradiation-Induced Deep Level In N-Type Gan, Z-Q. Fang, Joseph W. Hemsky, David C. Look, M. P. Mack
Physics Faculty Publications
Deep-level transient spectroscopy measurements of n-type GaN epitaxial layers irradiated with 1-MeV electrons reveal an irradiation-induced electron trap at EC−0.18 eV. The production rate is approximately 0.2 cm−1, lower than the rate of 1 cm−1 found for the N vacancy by Hall-effect studies. The defect trap cannot be firmly identified at this time. ©1998 American Institute of Physics.
Hopping Conduction In Molecular Beam Epitaxial Gaas Grown At Very Low Temperatures, David C. Look, Z-Q. Fang, J. W. Look, J. R. Sizelove
Hopping Conduction In Molecular Beam Epitaxial Gaas Grown At Very Low Temperatures, David C. Look, Z-Q. Fang, J. W. Look, J. R. Sizelove
Physics Faculty Publications
Conductivity and Hall effect measurements have been performed on 2 μm thick molecular beam epitaxial layers grown at very low substrate temperatures, 200 to 400°C. For growth temperatures below 300°C, the conduction is dominated by hopping between arsenic antisite defects of concentrations up to 1020 cm−3. Below measurement temperatures of about 130 K, the hopping conduction can be quenched by strong IR light illumination, because the antisite then becomes metastable. The antisite has a thermal activation energy of , and thus is not identical to the famous EL2. Both nearest‐neighbor and variable‐range hopping mechanisms are considered in …
Contact Resistance Measurements In Gaas Mesfet's And Modfet's By The Magneto‐Tlm Technique, David C. Look
Contact Resistance Measurements In Gaas Mesfet's And Modfet's By The Magneto‐Tlm Technique, David C. Look
Physics Faculty Publications
The standard transmission‐line model (TLM) for specific contact resistivity measurements of planar contacts is improved in two ways: (i) the addition of a magnetic field, which gives the mobility and carrier concentration of the bulk material, and the mobility of the material under the contact; and (ii) an extension to two layers, which makes the model applicable to MODFET structures. The results are applied to MESFET material, and MODFET material. One conclusion concerning the latter material is that the electrons directly beneath the annealed Au/Ge/Ni contacts have lower mobility than those in the bulk, but still …
Electrical Characterization Of Ion Implantation Into Gaas, David C. Look
Electrical Characterization Of Ion Implantation Into Gaas, David C. Look
Physics Faculty Publications
Recent advances in the characterization of ion‐implanted samples have included whole wafer mapping (topography) and depth profiling techniques. We review several methods for mapping electrical parameters, including the dark‐spot resistance (DSR), and the microwave photoconductance techniques. In addition, we suggest a new photo‐Hall technique which would allow mobility and carrier‐concentration mapping as well as that of resistivity . Finally, we review methods for obtaining ρ, μ, and depth profiles, with particular emphasis on the application of the magnetoresistance techniques in actual field‐effect transistor structures.