Characterization of High Quality Continuous GaN Films Grown on Si-Doped Cracked GaN Template

2003 ◽  
Vol 764 ◽  
Author(s):  
C. B. Soh ◽  
J. Zhang ◽  
D.Z. Chi ◽  
S. J. Chua
Keyword(s):  
Plasma Etching ◽  
Edge Dislocation ◽  
Deep Level ◽  
Device Fabrication ◽  
Trap Level ◽  
Device Structure ◽  
High Quality ◽  
Si Doped ◽  
Additional Defect ◽  
Trap Levels

AbstractIn this paper, deep level defects in high quality continuous GaN films grown over a cracked Si-doped GaN template has been studied using digital deep level transient spectroscopy (DLTS) and transmission electron microscopy (TEM). From TEM observation, it is found that the density of pure screw dislocations have been effectively suppressed while pure edge dislocations remained in substantial quantity. From DLTS measurement, trap levels at Ec -ET ∼ 0.11-0.12 eV, 0.24-0.27 eV, 0.60-0.63 eV were detected in the high quality GaN layer. DLTS measurement was also carried out on the underlying cracked Si-doped GaN template after the top high quality continuous GaN film was removed by plasma etching. An additional defect level at Ec-Et ∼ 0.37 eV was detected which we attributed to defect decoration at screw dislocation. Both the trap levels Ec-ET ∼ 0.24–0.27 eV, 0.60-0.63 eV are believed to originate from mixed screw/edge dislocation based on observation of the logarithmic capture behavior. Trap level at Ec -ET ∼ 0.24-0.27eV, however, experiences a more drastic increase in transient capacitance (i.e. in trap concentration) compared to that of Ec -ET ∼ 0.60-0.63 eV after plasma etching, illustrating that the latter is related to a higher proportion of edge dislocation. The 0.11-0.12 eV trap level, which exhibits an exponential capture kinetic, is believed to be related to nitrogen vacancies. This high quality continuous GaN layer can be used as a template to grow any device structure and the underneath cracked Si-doped GaN layer may help to release stress for the top continuous GaN layer. This can bring about a cracked free epilayer for subsequent device fabrication.

Comparative Study of trap levels observed in undoped and Si-doped GaN

2002 ◽  
Vol 719 ◽  
Author(s):  
C. B. Soh ◽  
D. Z. Chi ◽  
H. F. Lim ◽  
S. J. Chua
Keyword(s):  
Dislocation Density ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
The Other ◽  
Trap Level ◽  
Extended Defect ◽  
Si Doped ◽  
Transient Spectroscopy ◽  
Additional Defect ◽  
Trap Levels

AbstractIn this paper, deep level defects in undoped and Si–doped GaN have been studied using digital deep level transient spectroscopy. Common trap levels at Ec -ET ∼ 0.15-0.20 eV and 0.59-0.62 eV were detected for both undoped and Si-doped samples. For the doped samples, three additional defect levels at Ec-Et ∼ 0.11, 0.28, and 0.45 eV were detected. The concentration of the 0.15-0.20 eV was found to be much higher in undoped GaN that also shows higher dislocation density. Based on this correlation and the logarithmic capture behavior observed for this level, indicative of extended defect nature, we attribute the 0.15-0.20 eV level to dislocation related defects. On the other hand, the 0.28 and 0.45eV trap levels are tentatively attributed to Sirelated defects simply due to the fact that these two levels were observed only in Si-doped GaN. The 0.11eV trap level, which exhibits an exponential capture kinetic, is believed to be related to nitrogen vacancies.

DLTS AS A LOCAL PROBE OF CONCENTRATION AND DEPTH OF TRAP LEVELS

1994 ◽  
Vol 08 (13) ◽  
pp. 1765-1779 ◽  
Author(s):  
V. NÁDAŽDY ◽  
I. THURZO
Keyword(s):  
Deep Level ◽  
Direct Determination ◽  
Trap Depth ◽  
Pulse Mode ◽  
Detection Sensitivity ◽  
Trap Level ◽  
Charge Balance ◽  
Single Temperature ◽  
Transient Spectroscopy ◽  
Trap Levels

Complementarity of the capacitance and charge deep level transient spectroscopy (DLTS) is the idea which led us to an advanced method for profiling trap levels in semiconductors. This unifying approach to the space-charge spectroscopy, on grounds of applying the small-amplitude-filling pulse mode and evaluating the trapped charge balance, allows one to implement it in practice while using currently available instrumentation. A simple formalism is sufficient to obtain the demanded trap level depth. The usefulness of this method is demonstrated on bulk traps found in two different metal-insulator-semiconductor (MIS) capacitors. We propose also a new experimental technique providing the option of a direct determination of the trap depth from a single temperature scan. In addition, we found an expression for the relative detection sensitivity of the capacitance DLTS and justified quantitatively the earlier reported improved relative sensitivity of the charge transient spectroscopy.

Growth of Silicon-Doped and High Quality, Highly Resistive GaN for FET Applications

1995 ◽  
Vol 395 ◽  
Author(s):  
K. Doverspike ◽  
A.E. Wickenden ◽  
S.C. Binari ◽  
D.K. Gaskill ◽  
J.A. Freitas
Keyword(s):  
Operating Temperature ◽  
High Mobility ◽  
Growth Characteristics ◽  
Device Structure ◽  
High Quality ◽  
Capping Layer ◽  
Channel Layer ◽  
Si Doped ◽  
Silicon Doped ◽  
Recessed Gate

ABSTRACTWe have shown the ability to grow thin, high mobility, GaN channel layers on high quality, highly resistive GaN. The growth, characteristics, and device results of two types of MESFET structures were discussed. The first device structure consists of a 2000Ǻ, 2 × 1017cm−3 Si-doped channel layer, grown on 3µm of highly resistive GaN, while die second structure (recessed-gate MESFET) had a 1000Ǻ, 1 × 1018cm−3 Si-doped, n+ capping layer deposited on a 2000Ǻ, 2 × 1017cm−3 Si-doped channel layer. The first MESFET structure was operational at 500°C which is the highest reported operating temperature for a GaN device while the recessed-gate MESFET had a gmas high as 41mS/mm, which is the highest reported value for a GaN MESFET.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

Traps in Si-doped AlxGa1-xN Grown by Molecular Beam Epitaxy on Sapphire Characterized by Deep Level Transient Spectroscopy

2006 ◽  
Vol 955 ◽  
Author(s):  
Mo Ahoujja ◽  
S Elhamri ◽  
M Hogsed ◽  
Y. K. Yeo ◽  
R. L. Hengehold
Keyword(s):  
Molecular Beam Epitaxy ◽  
Deep Level Transient Spectroscopy ◽  
Molecular Beam ◽  
Deep Level ◽  
Unknown Origin ◽  
Shallow Donor ◽  
Related Point ◽  
Line Defects ◽  
Si Doped ◽  
Transient Spectroscopy

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.

Nanoscale Deep Level Defect Correlation with Schottky Barriers in 4H-SiC/Metal Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 907-910
Author(s):  
Sergey P. Tumakha ◽  
L.M. Porter ◽  
D.J. Ewing ◽  
Qamar-ul Wahab ◽  
X.Y. Ma ◽  
...  
Keyword(s):  
Surface Defect ◽  
Deep Level ◽  
Polarized Light ◽  
Schottky Barriers ◽  
Double Barrier ◽  
Barrier Heights ◽  
Current Voltage ◽  
Cathodoluminescence Spectroscopy ◽  
Morphological Defects ◽  
Additional Defect

We have used depth-resolved cathodoluminescence spectroscopy (DRCLS) to correlate subsurface deep level emissions and double barrier current-voltage (I-V) characteristics across an array of Ni/4H-SiC diodes on the same epitaxial wafer. These results demonstrate not only a correspondence between these optical features and measured barrier heights, but they also suggest that such states may limit the range of SB heights in general. DRCLS of near-ideal diodes show a broad 2.45 eV emission at common to all diode areas and associated with either impurities or inclusions. Strongly non-ideal diodes exhibit additional defect emissions at 2.2 and 2.65 eV. On the other hand, there is no correlation between the appearance of morphological defects observed by polarized light microscopy or X-ray topography and the presence of double barrier characteristics. The DRCLS observations of defect level transitions that correlate with non-ideal Schottky barriers suggest that these sub-surface defect features can be used to predict Schottky barrier behavior.

Growth of High-Quality Si-Doped AlGaN by Low-Pressure Metalorganic Vapor Phase Epitaxy

2011 ◽  
Vol 50 (9) ◽  
pp. 095502 ◽  
Author(s):  
Yuki Shimahara ◽  
Hideto Miyake ◽  
Kazumasa Hiramatsu ◽  
Fumitsugu Fukuyo ◽  
Tomoyuki Okada ◽  
...  
Keyword(s):  
Vapor Phase ◽  
Low Pressure ◽  
Metalorganic Vapor Phase Epitaxy ◽  
Vapor Phase Epitaxy ◽  
High Quality ◽  
Si Doped

Electrical and Optical Properties of Vanadium in Omvpe-Grown GaAs

1989 ◽  
Vol 145 ◽  
Author(s):  
W. S. Hobson ◽  
S. J. Pearton ◽  
V. Swaminathan ◽  
A. S. Jordan ◽  
Y. J. Kao ◽  
...  
Keyword(s):  
Deep Level ◽  
Vanadium Content ◽  
Epitaxial Layers ◽  
Electrical And Optical Properties ◽  
Vanadium Concentration ◽  
Co Doping ◽  
Undoped Material ◽  
Maximum Value ◽  
Si Doped ◽  
Transient Spectroscopy

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.

A New Approach Using Artificial Substrates for Growth of High-Quality Precipitate-Free HTS Thin Films, Toward Electronic Device Applications

2005 ◽  
Vol 868 ◽  
Author(s):  
K. Endo ◽  
P. Badica ◽  
H. Sato ◽  
H. Akoh
Keyword(s):  
Thin Films ◽  
Electronic Device ◽  
Growth Conditions ◽  
Device Fabrication ◽  
Artificial Substrates ◽  
High Quality ◽  
New Approach ◽  
Mesa Structure ◽  
Device Applications ◽  
And Performance

AbstractHigh quality thin films of HTS have been grown by MOCVD on substrates with artificial steps of predefined height and width. The surface of the films grown on the steps having width equal to the ‘double of the migration length' of the atomic species depositing on the substrate is totally free of precipitates: precipitates are gathered at the step edges where the free energy is lowest. The method has several advantages: it is simple, universal (it is independent of the materials, substrates, deposition technique or application) and allows control of precipitates segregates so that the quality and growth conditions of the films are the same as for the films grown on conventional substrates. The method is expected to result in new opportunities for the device fabrication, design and performance. As an example we present successful fabrication of a mesa structure showing intrinsic Josephson effect. We have used thin films of Bi-2212/Bi-2223 superstructure grown on (001) SrTiO3 single crystal substrates with artificial steps of 20 μm.

New viewpoint about the persistent luminescence mechanism of Mn2+/Eu3+ co-doped Zn2GeO4

2019 ◽  
Vol 33 (32) ◽  
pp. 1950389
Author(s):  
Zhou Wang ◽  
Zhiting Tang ◽  
Xueling Peng ◽  
Chuanhui Xia ◽  
Feng Wang
Keyword(s):  
Band Structure ◽  
Density Functional ◽  
Solid Phase ◽  
Density Functional Theory Calculation ◽  
Phase Method ◽  
Trap Level ◽  
Persistent Luminescence ◽  
Green Fluorescence ◽  
Co Doped ◽  
Trap Levels

In this work, Mn[Formula: see text]Eu[Formula: see text] co-doped Zn2GeO4 (Zn2GeO4:Mn[Formula: see text] was prepared by high-temperature solid phase method. Compared with common fluorescent materials Zn2GeO4:Mn[Formula: see text], Zn2GeO4:Mn[Formula: see text] could not only emit strong green fluorescence of 535 nm, but also maintain excellent persistent luminescence performance. Through Density Functional Theory calculation, we obtained the fine band structure of Zn2GeO4:Mn[Formula: see text]. The results of the band structure were consistent with the experimental spectral data. On this basis, we proposed a new luminescence mechanism model of Zn2GeO4:Mn[Formula: see text] to explain the phenomena observed in experiment reasonably, though which was not completely consistent with previous works. When Zn2GeO4:Mn[Formula: see text] was excited, electron–hole separation occurred in the valence band (VB), and the electron transitioned to the conduction band (CB) directly. Through CB, the electron was trapped by trap levels (7F[Formula: see text]F5 of Eu[Formula: see text] and maintained metastable for a long time. Under the action of thermal stimulation, electron returned to CB from the trap level slowly. The electron was captured again by the 4T2(D) level of Mn[Formula: see text]. Then the electron transitioned down toward VB and recombined with the previous hole and emitted a photon with 535 nm (afterglow). The samples were being irradiated, trap levels accommodated the excited electrons to saturation. More electrons excited into the CB could not be captured by the trap levels any more. They were captured directly by the 4T2(D) and transitioned directly to VB, then emitted green fluorescence.

Sign in / Sign up

Export Citation Format

Share Document