Low Temperature Growth of Oriented Gallium Nitride using Pulsed Laser Deposition

1995 ◽  
Vol 395 ◽  
Author(s):  
Robert Leuchtner ◽  
W. Brock ◽  
Y. Li ◽  
L. Hristakos
Keyword(s):  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Ambient Pressure ◽  
Pulsed Laser ◽  
Target Material ◽  
Deposition Process ◽  
Film Deposition ◽  
Laser Deposition ◽  
Metal Target ◽  
X Ray

ABSTRACTOriented GaN has been successfully grown at low substrate temperatures (∼480°C) on a- and r-planes of sapphire, using the pulsed laser deposition process. We have examined the effects of several deposition parameters on film growth, including substrate temperature (∼50–500°C), ambient pressure (1×10−3 – 10 torr of NH3), and target material (Ga or GaN). The film deposition rate was typically ∼3–4 μm/hr. Film characterization was performed using x-ray diffraction (XRD), optical microscopy, x-ray photoelectron spectrometry (XPS), and atomic force microscopy (AFM). In the case of the Ga metal target, a plasma (∼500V) between the target and substrate was necessary to promote formation of the GaN phase. The ammonia ambient enhanced the nitrogen content in the films compared to vacuum deposition. In general, the GaN target yielded better quality films (smaller rocking curve widths and smoother film morphology) compared to the Ga metal target. These results suggest that pulsed laser deposition is a promising approach to fabricating high quality films of this potentially important semiconducting material.

High Throughput Optimization of Y-Type Magnetoplumbite Epitaxial thin Film Growth by Combinatorial Pulsed Laser Deposition Technique

2001 ◽  
Vol 700 ◽  
Author(s):  
I. Ohkubo ◽  
Y. Matsumoto ◽  
M. Ohtani ◽  
T. Hasegawa ◽  
K. Ueno ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Buffer Layer ◽  
Film Growth ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Thin Film Growth ◽  
Laser Deposition ◽  
Throughput Optimization ◽  
Tem Analysis ◽  
First Time

AbstractThin films of Y-type magnetoplumbite (Ba2Co2Fe12O22: Co2Y) with such a huge unit cell length as 43.5 Å has been successfully fabricated for the first time with the aid of combinatorial optimization of pulsed laser deposition process. Planning a thickness gradient CoO buffer layer on MgAl2O4(111) substrate was very effective for prevent the phase separation of Co deficient impurity (BaFe2O4) to reside in the formation of desired Co2Y phase.From the TEM analysis, the CoO buffer layer of optimum thickness was incorporated into the Co2Y film to make theinterface with the make an atomically sharp.

A Numerical Simulation of Pulsed Laser Deposition

1994 ◽  
Vol 354 ◽  
Author(s):  
William T. Laughlin ◽  
Edmond Y. Lo
Keyword(s):  
Numerical Simulation ◽  
Pulsed Laser Deposition ◽  
Cross Sections ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Laser Wavelength ◽  
Film Deposition ◽  
Laser Deposition ◽  
Laser Fluences ◽  
Deposition Parameters

AbstractA numerical simulation of the pulsed laser deposition process has been developed. This model is applied to pulsed laser deposition of carbon, a solid lubricant material. At laser fluences above the ablation threshold, the vapor density and temperature at the substrate are sufficiently high that a continuum flow exists. For typical pulsed laser deposition parameters, plume vapor temperatures and densities are insufficient for significant ionization. However, plume absorption does take place and is regulated by wavelength dependent absorption cross sections of the molecular species. Vapor expansion velocities depend on the absorption of laser radiation and thus the laser wavelength. A simple kinetic theory of deposition predicts the film deposition rate and film thickness profile.

Pulsed Laser Deposition of Laterally Graded X-Ray Optical Multilayers on Substrates of Technical Relevance

1995 ◽  
Vol 382 ◽  
Author(s):  
R. Dietsch ◽  
TH. Holz ◽  
R. Krawietz ◽  
H. Mai ◽  
B. SchÖneich ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Thickness Distribution ◽  
Pulsed Laser ◽  
Single Layer ◽  
Thin Film Deposition ◽  
Optical Quality ◽  
Film Deposition ◽  
Laser Deposition ◽  
Emission Characteristic ◽  
X Ray

ABSTRACTPulsed Laser Deposition (PLD) is used for the preparation of Ni/C, W/C, and Mo/Si multilayers having X-ray optical quality. For the synthesis of layer stacks involving a uniform or a graded thickness distribution across 4"-wafers the conventional thin film deposition equipment of PLD has been modified. This modification provides a precise spatial control of the plasma plume orientation in the deposition chamber. With this arrangement the emission characteristic of the plasma source can be computer controlled and the desired coating profile can be tailored across an extended substrate via a stepper-motor-driven target manipulator.Thus film thickness uniformity (δts < 2%) is obtained on substrates up to 4" diameter even for smaller target-substrate distances. For laterally graded Ni and C individual layers linear thickness gradients of dts/dx = 3.2 × 10−8 were confirmed over the total substrate length by spectroscopic ellipsometry. The parameters deduced from single layer deposition were applied for the synthesis of laterally graded Ni/C multilayers. A mean value of the gradient of the stack period thickness dt/dx = 6.2 × 10−8 confirmed by X-ray reflectometry (nominal value: dt0 /dx = 6.4×10−8 ) characterizes precision and reproducibility of the coating process.

The Influence of Deposition Pressure on the Incorporation of Target and Ambient Oxygen Into Laser Ablated Material

1993 ◽  
Vol 311 ◽  
Author(s):  
M. Zhu Tidrow ◽  
S.S. Tidrow ◽  
W.W. Wilber ◽  
R.R. Pfeffer
Keyword(s):  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Target Material ◽  
Laser Deposition ◽  
Chamber Pressure ◽  
Ambient Atmosphere ◽  
Deposition Pressure ◽  
Amorphous Films ◽  
Ambient Oxygen

ABSTRACTOxygen plays an essential role in the growth of a variety of oxides such as high-Tc superconductors, ferroelectrics, ferrites and dielectrics. The oxygen available for film growth during laser ablation can come from two sources: the target material and the ambient deposition atmosphere. The amount of oxygen incorporated from these two sources at room temperature has been investigated over a range of deposition pressures. Thiswas accomplished using 18O as a tracer during pulsed laser deposition of amorphous filmsfrom Cu and CuO targets. It was found that the total amount of oxygen incorporated by the amorphous films increases with chamber pressure up to approximately 35 mTorr. For pulsed laser deposition from the oxide target, the major fraction of the oxygen within the deposited material comes from the target. For the oxide target, the amount of oxygen incorporated from the ambient atmosphere is strongly pressure dependent with a maximum near 35 mTorr. These results are compared to earlier work with YBa2Cu3O7.

scholarly journals Collisional Effects of Background Gases on Pulsed Laser Deposition Plasma Beams

1995 ◽  
Vol 388 ◽  
Author(s):  
David B. Geohegan ◽  
Alex A. Puretzky
Keyword(s):  
Pulsed Laser Deposition ◽  
Film Growth ◽  
Pulsed Laser ◽  
Target Material ◽  
Ion Flux ◽  
Fast Component ◽  
Laser Deposition ◽  
Optical Absorption Spectroscopy ◽  
Single Element ◽  
General Effect

AbstractThe penetration of energetic pulsed ablation plumes through ambient gases is experimentally characterized to investigate a general phenomenon believed to be important to film growth by pulsed laser deposition (PLD). Under typical PLD conditions involving background gases, the ion flux in the ablation plume is observed to split into distinct fast and slow components over a limited range of distances1,2 the fast component is transmitted with near-initial velocities and high kinetic energies, potentially damaging to growing films at these distances. Formation of the second, significantly-slowed component correlates with the bright contact front3 formation observed1,4 in fast ICCD imaging studies. This general effect is explored in detail for the case of yttrium ablation into argon, a single-element target into an inert gas.5 Time-resolved optical absorption spectroscopy and optical emission spectroscopy are employed to simultaneously view the populations of both excited and ground states of Y and Y+ for comparison with quantitative intensified-CCD photography of the visible plume luminescence and ion flux measurements made with fast ion probes during this phenomenon. these measurements confirm that, in addition to the bright significantly-slowed front which has been described by shock or drag propagation models1, a fast-component of target material is transmitted to extended distances for some ambient pressures with near-initial velocities.

Sign in / Sign up

Export Citation Format

Share Document