Midgap electron traps in n-type GaAs epitaxial layers grown by the close-spaced vapor transport technique

1991 ◽  
Vol 69 (3-4) ◽  
pp. 407-411 ◽  
Author(s):  
T. Bretagnon ◽  
A. Jean ◽  
P. Silvestre ◽  
S. Bourassa ◽  
R. Le Van Mao ◽  
...  

The deep-level transient spectroscopy technique was applied to the study of deep electron traps existing in n-type GaAs epitaxial layers that were prepared by the close-spaced vapor transport technique using three kinds of sources (semi-insulator-undoped, Zn-doped and Si-doped GaAs). Two midgap electron traps labelled ELCS1 and EL2 were observed in all layers regardless of the kind of source used. In addition, the effect of the electric field on the emission rate of ELCS1 is discussed and its identification to ETX2 and EL12 is suggested.

2002 ◽  
Vol 719 ◽  
Author(s):  
Masashi Kato ◽  
Masaya Ichimura ◽  
Eisuke Arai ◽  
Shigehiro Nishino

AbstractEpitaxial layers of 4H-SiC are grown on (0001) substrates inclined toward <1120> and <1100> directions. Defects in these films are characterized by deep level transient spectroscopy (DLTS) in order to clarify the dependence of concentrations and activation energies on substrate inclination. DLTS results show no such dependence on substrate inclination but show thickness dependence of the concentration.


2006 ◽  
Vol 955 ◽  
Author(s):  
Mo Ahoujja ◽  
S Elhamri ◽  
M Hogsed ◽  
Y. K. Yeo ◽  
R. L. Hengehold

ABSTRACTDeep levels in Si doped AlxGa1−xN samples, with Al mole fraction in the range of x = 0 to 0.30, grown by radio-frequency plasma activated molecular beam epitaxy on sapphire substrates were characterized by deep level transient spectroscopy (DLTS). DLTS measurements show two significant electron traps, P1 and P2, in AlGaN at all aluminum mole fractions. The electron trap, P2, appears to be a superposition of traps A and B , both of which are observed in GaN grown by various growth techniques and are thought to be related to VGa-shallow donor complexes. Trap P1 is related to line defects and N-related point defects. Both of these traps are distributed throughout the bulk of the epitaxial layer. An additional trap P0 which was observed in Al0.20Ga0.80N and Al0.30Ga0.70N is of unknown origin, but like P1 and P2, it exhibits dislocation-related capture kinetics. The activation energy measured from the conduction band of the defects is found to increase with Al mole content, a behavior consistent with other III-V semiconductors.


1989 ◽  
Vol 145 ◽  
Author(s):  
W. S. Hobson ◽  
S. J. Pearton ◽  
V. Swaminathan ◽  
A. S. Jordan ◽  
Y. J. Kao ◽  
...  

AbstractThe electrical and photoluminescent properties of vanadium incorporated into GaAs epitaxial layers from a VO(OC2 H5)3 source during organometallic vapor phase epitaxy were examined. The vanadium concentration in the GaAs was controllably varied from 1016 to 1018 atoms cm−3. Deep level transient spectroscopy showed the presence of an electron trap at Ec – 0.15 eV which increased in concentration with vanadium content of the epitaxial layers. A maximum value of 8 × 1015 cm−3 for this trap was obtained. There were no midgap electron traps associated with vanadium. In intentionally Si-doped epitaxial layers, co-doping with vanadium was observed to have no effect in reducing the carrier density when the Si concentration was > 4 × 1016 cm−3. The net carrier concentration profiles resulting from 29 si implantation into GaAs containing 1018 cm−3of total V had sharper tails than for similar implantation into undoped material, indicating the presence of less than 1016 cm−3V-related acceptors. Photoluminescent spectra exhibited the characteristic V+3intracenter emission at 0.65∼0.75 eV. No other deep level photoluminescence was detected. For a V concentration of 1016 cm−3only 2.5 × 1013 cm−3was electrically active. Over the entire V concentration investigated this impurity was predominantly (≥99%) inactive.


1988 ◽  
Vol 27 (Part 1, No. 2) ◽  
pp. 192-195 ◽  
Author(s):  
Kikuo Kobayashi ◽  
Masahiko Morita ◽  
Norihiko Kamata ◽  
Takeo Suzuki

1987 ◽  
Vol 92 ◽  
Author(s):  
Akio Kitagawa ◽  
Yutaka Tokuda ◽  
Akira Usami ◽  
Takao Wada ◽  
Hiroyuki kano

ABSTRACTRapid thermal processing (RTP) using halogen lamps for a Si-doped molecular beam epitaxial (MBE) n-GaAs layers was investigated by deep level transient spectroscopy. RTP was performed at 700°C, 800°C and 900°C for 6 s. Two electron traps NI ( Ec-0.5-0.7eV) and EL2 (Ec - 0.82 eV) are produced by RTP at 800 and 900°C.The peculiar spatial variations of the Nl and EL2 concentration across the MBE GaAs films are observed. The larger concentrations of the trap N1 and EL2 are observed near the edge of the samples, and the minima of N1 and EL2 concentration lie between the center and the edge of the sample. It seems that these spatial variations of N1 and EL2 concentration are consistent with that of the thermal stress induced by RTP. Furthermore, the EL2 concentration near the edge of the sample is suppressed by the contact with the GaAs pieces on the edge around the sample during RTP.


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