A STUDY OF THE ELECTRICAL PROPERTIES OF Al2O3 FILMS DEPOSITED ON GaAs SUBSTRATES BY SPRAY PYROLYSIS

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1637-1640 ◽  
Author(s):  
J. CHAVEZ-RAMIREZ ◽  
M. AGUILAR-FRUTIS ◽  
M. GARCIA ◽  
E. MARTINEZ ◽  
O. ALVAREZ-FREGOSO ◽  
...  

Electrical characteristics of high quality aluminum oxide thin films deposited by the spray pyrolysis technique on GaAs substrates are reported. The films were deposited using a spraying solution of aluminum acetylacetonate in N,N-dimethylformamide and an ultrasonic mist generator. The substrates were (100) GaAs wafers Si-doped (1018 cm -3). The substrate temperature during deposition was in the range of 300–600°C. The electrical characteristics of these films were determined by capacitance and current versus voltage measurements by the incorporation of these films into metal-oxide-semiconductor structures. The interface state density resulted in the order of 1012 1/ eV-cm 2 and the films can stand electric fields higher than 5 MV/cm, without observing a destructive dielectric breakdown. The refractive index, measured by ellipsometry at 633 nm, resulted close to 1.64. The determination of the chemical composition of the films was achieved by energy dispersive X-ray spectroscopy; it resulted close to that of stoichiometric aluminum oxide (O/Al = 1.5) when films are deposited at substrate temperatures of 300–350°C.

1994 ◽  
Vol 339 ◽  
Author(s):  
R. Turan ◽  
Q. Wahab ◽  
L. Hultman ◽  
M. Willander ◽  
J. -E. Sundgren

ABSTRACTWe report the fabrication and the characterization of Metal Oxide Semiconductor (MOS) structure fabricated on thermally oxidized 3C-SiC grown by reactive magnetron sputtering. The structure and the composition of the SiO2 layer was studied by cross-sectional transmission electron microscopy (XTEM) Auger electron spectroscopy (AES). Homogeneous stoichiometric SiO2 layers formed with a well-defined interface to the faceted SiC(lll) top surface. Electrical properties of the MOS capacitor have been analyzed by employing the capacitance and conductance techniques. C-V curves shows the accumulation, depletion and deep depletion phases. The capacitance in the inversion regime is not saturated, as usually observed for wide-bandgap materials. The unintentional doping concentration determined from the 1/C2 curve was found to be as low as 2.8 × 1015 cm-3. The density of positive charges in the grown oxide and the interface states have been extracted by using high-frequency C-V and conductance techniques. The interface state density has been found to be in the order of 1011cm2-eV-1.


2018 ◽  
Vol 4 (5) ◽  
pp. 542-545 ◽  
Author(s):  
R. Shabu ◽  
A. Moses Ezhil Raj

As major attention has been paid to transition metal oxide semiconductor suitable for solar cell, photo detector and gas sensor, present study embark on the structural, optical and electrical characterization of Ag doped CuO thin films prepared using chemical spray pyrolysis technique at the constant substrate temperature of 350 �C. For Ag doping, various concentrations of silver acetate (0.5-3.0 wt.%) was used in the sprayed precursor solution. Confirmed monoclinic lattice shows the tenorite phase formation of CuO in the pure and Ag doped films. The optical band gap of the films was in the range of 2.4 -3.4 eV. A minimum resistivity of 0.0017x103 ohmcm was achieved in the 0.5 wt.% Ag doped film, and its optical band gap was 2.74 eV.


1992 ◽  
Vol 268 ◽  
Author(s):  
Walter E. Mlynko ◽  
Srinandan R. Kasi ◽  
Dennis M. Manos

ABSTRACTNovel processing methods are being studied to address the highly selective and directional etch requirements of the ULSI manufacturing era; neutral molecular and atomic beams are two promising candidates. In this study, the potential of 5 eV neutral atomic oxygen beams for dry development of photoresist is demonstrated for application in patterning of CMOS devices. The patterning of photoresist directly on polysilicon gate layers enables the use of a self-contained dry processing strategy, with oxygen beams for resist etching and chlorine beams for polysilicon etching. Exposure to such reactive low-energy species and to the UV radiation from the line-of-sight, high-density plasma source can, however, alter MOSFET gate oxide quality, impacting device performance and reliability. We have studied this process-related device integrity issue by subjecting polysilicon gate MOS structures to exposure treatments of 5–20 eV oxygen beams similar to those used for resist patterning. Electrical characterization shows a significant increase in the oxide trapped charge (30–90x) and interface state density (30–60x) upon low-energy exposure. Current-voltage(IV) and dielectric breakdown characterization show increased low-field leakage characteristics for the same exposure. High-field electron injection studies reveal that the 0.25–V to 0.5–V negative flatband shifts (measured after oxygen beam exposure) can be partially annealed by carrier injection. This could be due to positive charge annihilation or electron trapping, or some combination of both. SEM and electrical analysis of structures exposed to neutral beam processing are presented along with the results of thermal annealing treatments.


2013 ◽  
Vol 740-742 ◽  
pp. 695-698 ◽  
Author(s):  
Tsuyoshi Akagi ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama ◽  
Takashi Fuyuki

Metal-oxide-semiconductor (MOS) capacitors with phosphorus localized near the SiO2/SiC interface were fabricated on 4H-SiC by direct POCl3treatment followed by SiO2deposition. Post-deposition annealing (PDA) temperature affected MOS device properties and phosphorus distribution in the oxide. The sample with PDA at 800 °C showed narrow phosphorus-doped oxide region, resulting in low interface state density near the conduction band edge and small flatband voltage shift after FN injection. The interfacial localization of phosphorus improved both interface properties and reliability of 4H-SiC MOS devices.


2016 ◽  
Vol 858 ◽  
pp. 663-666
Author(s):  
Marilena Vivona ◽  
Patrick Fiorenza ◽  
Tomasz Sledziewski ◽  
Alexandra Gkanatsiou ◽  
Michael Krieger ◽  
...  

In this work, the electrical properties of SiO2/SiC interfaces onto a 2°-off axis 4H-SiC layer were studied and validated through the processing and characterization of metal-oxide-semiconductor (MOS) capacitors. The electrical analyses on the MOS capacitors gave an interface state density in the low 1×1012 eV-1cm-2 range, which results comparable to the standard 4°-off-axis 4H-SiC, currently used for device fabrication. From Fowler-Nordheim analysis and breakdown measurements, a barrier height of 2.9 eV and an oxide breakdown of 10.3 MV/cm were determined. The results demonstrate the maturity of the 2°-off axis material and pave the way for the fabrication of 4H-SiC MOSFET devices on this misorientation angle.


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