Study of low-frequency excess noise in GaN thin films deposited by RF-MBE on intermediate-temperature buffer layers

2001 ◽  
Vol 48 (10) ◽  
pp. 2400-2404 ◽  
Author(s):  
Bong-Hung Leung ◽  
Wai-Keung Fong ◽  
Chang-Fei Zhu ◽  
C. Surya
Keyword(s):  
Thin Films ◽  
Low Frequency ◽  
Intermediate Temperature ◽  
Buffer Layers ◽  
Excess Noise

STUDY OF LOW-FREQUENCY EXCESS NOISE IN Ga-POLARITY GaN EPITAXIAL LAYERS

2001 ◽  
Vol 01 (04) ◽  
pp. R163-R174 ◽  
Author(s):  
J. Q. XIE ◽  
W. K. FONG ◽  
B. H. LEUNG ◽  
C. F. ZHU ◽  
C. SURYA ◽  
...  
Keyword(s):  
Thin Films ◽  
Flicker Noise ◽  
Substantial Reduction ◽  
Power Spectra ◽  
Low Frequency ◽  
Buffer Layers ◽  
Excess Noise ◽  
Rf Plasma ◽  
Noise Power ◽  
Scattering Rate

We report detailed investigations of low-frequency excess noise in Ga -polarity GaN thin films deposited by RF-plasma assisted molecular beam epitaxy. The noise properties of the GaN thin films deposited with and without the intermediate-temperature buffer layers (ITBL) are studied in detailed to examine the effects of the ITBL on the noise. Substantial reduction in the flicker noise levels are observed for samples grown on ITBLs with a Hooge parameter of 3×10-4, which is believed to be the lowest, to date, reported for GaN material. At low-temperatures, Lorentzian bumps originating from the generation-recombination processes are observed. Detailed studies of the temperature dependencies of the voltage noise power spectra have led to the formulation of a model for the observed low-frequency fluctuations. The model stipulates that the phenomenon arises from the thermally activated trapping and detrapping of carriers. The process results in the correlated fluctuations in the carrier number and the Coulombic scattering rate. Quantitative computation shows that number fluctuation dominates in our samples. Numerical evaluation of the deep-levels indicates substantial reduction in the trap density for the Ga -polarity GaN films.

Low-frequency excess noise in YBCO thin films near the transition temperature

1993 ◽  
Author(s):  
Sisi Jiang ◽  
Peter Hallemeier ◽  
Charles Surya ◽  
Julia M. Phillips
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Low Frequency ◽  
Excess Noise ◽  
Ybco Thin Films

Light Scattering from Pulsed Laser Deposited BaBi4Ti4O15 Thin Films

2000 ◽  
Vol 623 ◽  
Author(s):  
R.K. Soni ◽  
Anju Dixit ◽  
R. S. Katiyar ◽  
A. Pignolet ◽  
K.M. Satyalakshmi ◽  
...  
Keyword(s):  
Thin Films ◽  
Light Scattering ◽  
Room Temperature ◽  
Layer Structure ◽  
Low Frequency ◽  
Pulsed Laser ◽  
Buffer Layers ◽  
Frequency Mode ◽  
High Frequency Vibrations ◽  
Low Frequency Mode

AbstractLight scattering investigations are carried out on BaBi4Ti4O15 (BBiT) which is a member of the Bi-layer structure ferroelectric oxide with n = 4. The BBiT thin films, thickness ∼ 300 nm, were grown on epitaxial conducting LaNiO3 electrodes on epitaxial buffer layers on (100) silicon by pulsed laser deposition. Micro-Raman measurements performed on these films reveal a sharp low-frequency mode at 51 cm−1 along with broad highfrequeficy modes corresponding to other lattice vibrations including TiO6 octahedra. No temperature dependence of the low frequency mode is seen while a weak dependence of the broad high frequency vibrations are observed in the mixed oriented regions. Raman polarization carried out at room temperature indicates that the prominent modes have Alg and Eg symmetries in the BaBi4Ti4O15 thin films.

Characterization Of G-R Noise In GaN Films Grown By RF-MBE On Intermediate-Temperature Buffer Layers

2001 ◽  
Vol 693 ◽  
Author(s):  
W.K. Fong ◽  
B.H. Leung ◽  
C.F. Zhu ◽  
Charles Surya
Keyword(s):  
Buffer Layer ◽  
Defect Density ◽  
Strong Dependence ◽  
Power Spectra ◽  
Low Frequency ◽  
Intermediate Temperature ◽  
Buffer Layers ◽  
Rf Plasma ◽  
Frequency Noise ◽  
Noise Power

AbstractWe report detailed investigations of generation-recombination (G-R) noise in GaN films grown by rf-plasma assisted molecular beam epitaxy on intermediate-temperature buffer layer (ITBL) in addition to conventional low-temperature buffer layer. To characterize the film quality affected by the use of ITBL, low-frequency noise measurements were performed. The voltage noise power spectra show a strong dependence on the thickness of the ITBL. A model has been presented to explain the observed G-R noise, which stipulates that the phenomenon arises from the thermally activated trapping and detrapping of carriers by traps. The process leads to the correlated fluctuations in both the carrier number and the coulombic scattering rate. Detailed numerical evaluation shows that number fluctuation dominates in our samples. The calculated trap densities show that the use of ITBL can effectively reduce defect density by over an order of magnitude.

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