UV Photostimulated Si Atomic-Layer Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
D. Lubben ◽  
R. Tsu ◽  
T. R. Bramblett ◽  
J. E. Greene
Keyword(s):  
Film Growth ◽  
Laser Energy ◽  
Reaction Pathway ◽  
Atomic Layer ◽  
Laser Pulses ◽  
Growth Cycle ◽  
Atomic Layer Epitaxy ◽  
Extended Defects ◽  
Wide Range ◽  
Si Films

ABSTRACTSingle-crystal Si films have been grown on Si(001)2×1 substrates by UVphotostimulated atomic-layer epitaxy (ALE) from Si2H6. The ALE deposition rate R per growth cycle remains constant at 0.4 monolayers (ML) over a wide range of deposition parameters: growth temperature (Ts= 180–400 °C), Si2H6 exposure (peak pressure during gas pulse = 0.1−5 mTorr), laser energy density ( = 250–450 mJ cm−2 where is determined by Ts), and number of UV laser pulses per cycle. A film growth mocrel, based upon the results of the present deposition experiments and Monte Carlo simulations, together with our previous adsorption/desorption measurements, Is used to describe the reaction pathway for the process. The Hterminated silylene-saturated surface formed by adsorption and desorption of disilene is thermally stable and passive to further Si2H6 exposure. ArF or KrF laser pulses (≅20 ns) are used to desorb H, following a Si2H6 exposure, and the growth cycle is repeated until the desired film thickness is obtained. At Ts < 180 °C, the growth process becomes rate limited by the surface dissociation step and R decreases exponentially as a function of 1/Ts with an activation energy of ≅0.5 eV. At Ts > 400 °C, H is thermally desorbed and pyrolytic growth competes with ALE. Transmission electron micrographs together with selected-area electron diffraction patterns show that the ALE films are epitaxial layers with no observed extended defects or strain.

Atomic Layer Epitaxy of GaAs on Si by Mocvd

1989 ◽  
Vol 145 ◽  
Author(s):  
N.H. Karam ◽  
V.E. Haven ◽  
S.M. Vernon ◽  
J.C. Tran ◽  
N.A. El-Masry
Keyword(s):  
Film Growth ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Deposition Technique ◽  
Nucleation Layer ◽  
Selective Area Epitaxy ◽  
Si Substrates ◽  
Gaas On Si ◽  
Gaas Films ◽  
Si Films

AbstractEpitaxial GaAs films have been deposited on Si substrates using Atomic Layer Epitaxy (ALE) for the first time. This has been achieved in a SPI-MO CVD™ 450 reactor especially modified foroALE. After an initial high temperature bakeout, a nucleation layer 100-300 Å thick was deposited by ALE. Film growth was then resumed by conventional MOCVD to achieve the desired film thickness. The surface morphologies of the deposited films were found to be comparable to current state of the art conventional GaAs on Si films deposited by the two-step growth process in the same reactor.Selective area epitaxy of GaAs on Si has also been achieved on Si02-coated and patterned Si wafers. The standard two-step deposition technique resulted in epitaxial growth in the patterned windows and poly-GaAs on the oxide mask, while ALE growth resulted in deposition only in the etched windows with no poly-growth on the oxide mask. We will report on the potential of this new deposition technique in producing high quality GaAs-on-Si films.

Nanoscale Rapid Melting and Crystallization of Amorphous Silicon Thin Films

2005 ◽  
Author(s):  
A. Chimmalgi ◽  
D. J. Hwang ◽  
C. P. Griogoropoulos
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Laser Energy ◽  
Near Field ◽  
Field Enhancement ◽  
Laser Pulses ◽  
Nanosecond Laser ◽  
Rapid Melting ◽  
Si Films ◽  
Melting And Crystallization

Nanostructuring of thin films is gaining widespread importance owing to ever-increasing applications in a variety of fields. The current study details nanosecond laser-based rapid melting and crystallization of thin amorphous silicon (a-Si) films at the nanoscale. Two different near-field processing schemes were employed. In the first scheme, local field enhancement in the near-field of a SPM probe tip irradiated with nanosecond laser pulses was utilized. As a second approach, the laser beam was spatially confined by a cantilevered near field scanning microscope tip (NSOM) fiber tip. Details of various modification regimes produced as a result of the rapid a-Si melting and crystallization transformations that critically depend on the input laser fluence are presented. At one extreme corresponding to relatively high applied fluence, ablation area surrounded by a narrow melt region was observed. At the other extreme, where the incident laser energy density is much lower, single nanostructures with a lateral dimension of ~90 nm were defined. The ability to induce nucleation and produce single semiconductor nanostructures in a controlled fashion may be crucial in the field of nano-opto-electronics.

scholarly journals Interaction of annular-focused laser beams with solid targets

2015 ◽  
Vol 33 (3) ◽  
pp. 541-550 ◽  
Author(s):  
N.E. Andreev ◽  
M.E. Povarnitsyn ◽  
M.E. Veysman ◽  
A.YA. Faenov ◽  
P.R. Levashov ◽  
...  
Keyword(s):  
Laser Energy ◽  
Laser Pulses ◽  
Heavy Ion ◽  
High Energy ◽  
Weakly Coupled ◽  
Wide Range ◽  
Energy Laser ◽  
High Energy Laser ◽  
Hydrodynamic Code ◽  
Two Temperature

AbstractThe two-temperature, 2D hydrodynamic code Hydro–ELectro–IOnization–2–Dimensional (HELIO2D), which takes into account self-consistently the laser energy absorption in a target, ionization, heating, and expansion of the created plasma is elaborated. The wide-range two-temperature equation of state is developed and used to model the metal target dynamics from room temperature to the conditions of weakly coupled plasma. The simulation results are compared and demonstrated a good agreement with experimental data on the Mg target being heated by laser pulses of the nanosecond high-energy laser for heavy ion experiments (NHELIX) at Gesellschaft fur Schwerionenforschung. The importance of using realistic models of matter properties is demonstrated.

Low Temperature Laser-Doping Process Using PSG and BSG Films for Poly-Si TFTs

2000 ◽  
Vol 621 ◽  
Author(s):  
Cheon-Hong Kim ◽  
Sang-Hoon Jung ◽  
Jae-Hong Jeon ◽  
Min-Koo Han
Keyword(s):  
Energy Density ◽  
Low Temperature ◽  
Sheet Resistance ◽  
Laser Energy ◽  
Surface Concentration ◽  
Laser Pulses ◽  
Laser Energy Density ◽  
Silicon Thin Film ◽  
Laser Doping ◽  
Si Films

ABSTRACTA simple low-temperature excimer-laser doping process employing phosphosilicate glass (PSG) and borosilicate glass (BSG) films as dopant sources is proposed in order to form source and drain regions for polycrystalline silicon thin film transistors (poly-Si TFTs). We have successfully controlled sheet resistance and dopant depth profile of doped poly-Si films by varying PH3/SiH4 flow ratio, laser energy density and the number of laser pulses. The penetration depth and the surface concentration of dopants were increased with increasing laser energy density and the number of laser pulses. The minimum sheet resistance of 450ω/ for phosphorus (P) doping and 1100ω/ for boron (B) doping were successfully obtained. Our experimental results show that the proposed laser-doping process is suitable for source/drain formation of poly-Si TFTs.

In situ study of a strontium β-diketonate precursor for thin-film growth by atomic layer epitaxy

1994 ◽  
Vol 4 (8) ◽  
pp. 1239-1244 ◽  
Author(s):  
Jaan Aarik ◽  
Aleks Aidla ◽  
Andres Jaek ◽  
Markku Leskelä ◽  
Lauri Niinistö
Keyword(s):  
Thin Film ◽  
Film Growth ◽  
Atomic Layer ◽  
Thin Film Growth ◽  
Atomic Layer Epitaxy ◽  
In Situ Study

Laser Assisted Atomic Layer Epitaxy-A Vehicle to Optoelectronic Integration

1991 ◽  
Vol 222 ◽  
Author(s):  
Q. Chen ◽  
J. S. Osinski ◽  
C. A. Beyler ◽  
M. Cao ◽  
P. D. Dapkus ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Growth Parameters ◽  
Growth Parameter ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Gain Medium ◽  
Atomic Layer Epitaxy ◽  
Small Areas ◽  
Wide Range ◽  
Optoelectronic Integration

ABSTRACTTwo implementations of laser assisted atomic layer epitaxy(LALE) for selective area growth of GaAs using trimethylgallium and AsH3 as precursors are described. A wide range of growth parameters lead to self-limiting monolayer/cycle growth which is suited for precise layer thickness control. By combining LALE with conventional metalorganic chemical vapor deposition, A10.3Ga0.7As/GaAs double heterostructures including LALE GaAs have been grown, permitting electrical and optical characterization to be performed on the thin and small areas of the LALE deposits. The information is used in a growth parameter optimization process resulting in device quality GaAs. Quantum well lasers with active region grown by LALE are demonstrated for the first time. The application of LALE to optoelectronic integration is demonstrated by depositing small area quantum wells as the gain medium in an otherwise transparent waveguide.

Theoretical evaluation of film growth rate during atomic layer epitaxy

2000 ◽  
Vol 158 (1-2) ◽  
pp. 81-91 ◽  
Author(s):  
Hyung-Sang Park ◽  
Jae-Sik Min ◽  
Jung-Wook Lim ◽  
Sang-Won Kang
Keyword(s):  
Growth Rate ◽  
Film Growth ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Theoretical Evaluation ◽  
Film Growth Rate
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