Organometallic Chemical Vapor Deposition of Gaas Using Novel Organometallic Precursors

1988 ◽  
Vol 131 ◽  
Author(s):  
R. A. Jones ◽  
A. H. Cowley ◽  
B. L. Benac ◽  
K. B. Kidd ◽  
J. G. Ekerdt ◽  
...  
Keyword(s):  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Total System ◽  
Alkyl Aryl ◽  
Group V ◽  
Group Iii ◽  
Design And Synthesis ◽  
System Pressure ◽  
Organometallic Precursors

ABSTRACTThe goals of the research are the design and synthesis of a new class of precursor compounds for III/V compound semiconductor materials, growth of films with these precursors and developoment of an understanding of the relationships between precursor structure, film growth reactions and film properties. Conventional OMCVD of III/V compound materials has a number of inherent safety and processing problems associated with the group III alkyl and group V hydride sources. Our approach to these problems is the synthesis of a single precursor with a fixed III:V stoichiometry and a direct two center, two electron sigma III V bond., These, compounds have the general formula,[R2M(R 2 E)] 2 and R2M(R 2 E) 2M R2 (MM = Al, Ga, In; E=P, As; R, R = alkyl, aryl). The III V bond in these compounds is stronger than the other bonds and the minium deposition temperature can be controlled by employing subsituents that undergo facile hydrocarbon elimination.A typical example is the use of [Me 2Ga(µ t Bu 2 As)] 2 as the single source for GaAs films. The organometallic precursor is a solid crystalline powder which is maintained at 130°C to generate enough vapor for OMCVD. Typical film growth conditions involve the use of H2 or He as the carrier gas, substrate temperatures of 500 to 700°C, and a total system pressure of 0.0002 Torr. GaAs(100), Si(100) (As doped 30 off toward (011) and quartz have been used as substrates. Film composition has been established with XPS. The Ga 3d, As 3d, and C ls signals at 18.8, 40.9, and 284.6 eV, respectively, reveal the films to be 1:1 Ga:As and void of carbon. The carbon levels are less than 1000 ppm. X ray diffraction and SEM results suggest polycrystalline GaAs on quartz and epitaxial GaAs on GaAs(100) and Si(100). (2 K) photoluminescence measurements on GaAs, grown on semi insulating GaAs(100) and Si doped GaAs(0 100) at 570 C. produce PL signals indicating that crystalline domains are present, the measurements indicate degeneratively n doped material and show that good Ga:As ratios and low levels (ca. 1 ppm) of impurities are present. Growth rates:∼ 1.0 mm/hour.

Numerical Investigation of Pulsed Chemical Vapor Deposition of Aluminum Nitride to Reduce Particle Formation

2011 ◽  
Author(s):  
Derek Endres ◽  
Sandip Mazumder
Keyword(s):  
Gas Phase ◽  
Direct Contact ◽  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Particle Formation ◽  
Group V ◽  
Flow Rates ◽  
Group Iii ◽  
Reactor Pressure

Particles of aluminum nitride (AlN) have been observed to form during epitaxial growth of AlN films by metal organic chemical vapor deposition (MOCVD). Particle formation is undesirable because particles do not contribute to the film growth, and are detrimental to the hydraulic system of the reactor. It is believed that particle formation is triggered by adducts that are formed when the group-III precursor, namely tri-methyl-aluminum (TMAl), and the group-V precursor, namely ammonia (NH3), come in direct contact in the gas-phase. Thus, one way to eliminate particle formation is to prevent the group-III and the group-V precursors from coming in direct contact at all in the gas-phase. In this article, pulsing of TMAl and NH3 is numerically investigated as a means to reduce AlN particle formation. The investigations are conducted using computational fluid dynamics (CFD) analysis with the inclusion of detailed chemical reaction mechanisms both in the gas-phase and at the surface. The CFD code is first validated for steady-state (non-pulsed) MOCVD of AlN against published data. Subsequently, it is exercised for pulsed MOCVD with various pulse widths, precursor gas flow rates, wafer temperature, and reactor pressure. It is found that in order to significantly reduce particle formation, the group-III and group-V precursors need to be separated by a carrier gas pulse, and the carrier gas pulse should be at least 5–6 times as long as the precursor gas pulses. The studies also reveal that with the same time-averaged precursor gas flow rates as steady injection (non-pulsed) conditions, pulsed MOCVD can result in higher film growth rates because the precursors are incorporated into the film, rather than being wasted as particles. The improvement in growth rate was noted for both horizontal and vertical reactors, and was found to be most pronounced for intermediate wafer temperature and intermediate reactor pressure.

Computational Study of Pulsed Metal-Organic Chemical Vapor Deposition of Aluminum Nitride

2011 ◽  
Author(s):  
Derek Endres ◽  
Sandip Mazumder
Keyword(s):  
Gas Phase ◽  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Particle Formation ◽  
Organic Chemical ◽  
Group V ◽  
Group Iii ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Particles of aluminum nitride (AlN) have been observed to form during epitaxial growth of AlN films by metal organic chemical vapor deposition (MOCVD). Particle formation is undesirable because particles do not contribute to the film growth, and are detrimental to the hydraulic system of the reactor. It is believed that particle formation is triggered by adducts that are formed when the group-III precursor, namely tri-methyl-aluminum (TMAl), and the group-V precursor, namely ammonia (NH3), come in direct contact in the gas-phase. Thus, one way to eliminate particle formation is to prevent the group-III and the group-V precursors from coming in direct contact at all in the gas-phase. In this article, pulsing of TMAl and NH3 is numerically investigated as a means to reduce AlN particle formation. The investigations are conducted using computational fluid dynamics (CFD) analysis with the inclusion of detailed chemical reaction mechanisms both in the gas-phase and at the surface. The CFD code is first validated for steady-state (non-pulsed) MOCVD of AlN against published data. Subsequently, it is exercised for pulsed MOCVD with various pulse widths, precursor gas flow rates, wafer temperature, and reactor pressure. It is found that in order to significantly reduce particle formation, the group-III and group-V precursors need to be separated by a carrier gas pulse, and the carrier gas pulse should be at least 5–6 times as long as the precursor gas pulses. The studies also reveal that with the same time-averaged precursor gas flow rates as steady injection (non-pulsed) conditions, pulsed MOCVD can result in higher film growth rates because the precursors are incorporated into the film, rather than being wasted as particles. The improvement in growth rate was noted for both horizontal and vertical reactors, and was found to be most pronounced for intermediate wafer temperature and intermediate reactor pressure.

MOCVD Growth of InAlAsSb Layer for High-Breakdown Voltage HEMT Applications

2003 ◽  
Vol 799 ◽  
Author(s):  
Haruki Yokoyama ◽  
Hiroki Sugiyama ◽  
Yasuhiro Oda ◽  
Michio Sato ◽  
Noriyuki Watanabe ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Chemical Vapor ◽  
Composition Analysis ◽  
Group V ◽  
Group Iii ◽  
Mocvd Growth ◽  
Order Of Magnitude ◽  
Etch Stop ◽  
Etch Stop Layer ◽  
Inp Substrates

ABSTRACTThis paper studies the decomposition characteristic of group-III sources during InAlAsSb growth on InP substrates by metalorganic chemical vapor deposition (MOCVD) using trimethylindium (TMI), trimethylaluminum (TMA), trimethylantimony (TMSb) and arsine (AsH3). A composition analysis of InAlAsSb layers shows that the group-III compositions in the InAlAsSb layer change remarkably when the flow rate of the group-V source is varied. To clarify the reason for this phenomenon, the growth rates of InAsSb and AlAsSb component are examined. Their changes indicate that TMSb suppresses the decomposition of TMA while AsH3 enhances it. Moreover, the HEMT structure with InP/InAlAsSb Schottky barrier layer, whose InP layer acts as a recess-etch-stop layer, is fabricated for the first time. The I-V characteristics of a fabricated Schottky barrier diode indicate that the reverse leakage current of InP/InAlAsSb is about one order of magnitude smaller than that of commonly used InP/InAlAs.

Thin films for superconducting electronics: Precursor performance issues, deposition mechanisms, and superconducting phase formation-processing strategies in the growth of Tl2Ba2CaCu2O8 films by metal-organic chemical vapor deposition

1997 ◽  
Vol 12 (5) ◽  
pp. 1214-1236 ◽  
Author(s):  
Bruce J. Hinds ◽  
Richard J. McNeely ◽  
Daniel B. Studebaker ◽  
Tobin J. Marks ◽  
Timothy P. Hogan ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Pressure ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

Epitaxial Tl2Ba2CaCu2O8 thin films with excellent electrical transport characteristics are grown in a two-step process involving metal-organic chemical vapor deposition (MOCVD) of a BaCaCuO(F) thin film followed by a postanneal in the presence of Tl2O vapor. Vapor pressure characteristics of the recently developed liquid metal-organic precursors Ba(hfa)2 • mep (hfa = hexafluoroacetylacetonate, mep = methylethylpentaglyme), Ca(hfa)2 • tet (tet = tetraglyme), and the solid precursor Cu(dpm)2 (dpm = dipivaloylmethanate) are characterized by low pressure thermogravimetric analysis. Under typical film growth conditions, transport is shown to be diffusion limited. The transport rate of Ba(hfa)2 • mep is demonstrated to be stable for over 85 h at typical MOCVD temperatures (120 °C). In contrast, the vapor pressure stability of the commonly used Ba precursor, Ba(dpm)2, deteriorates rapidly at typical growth temperatures, and the decrease in vapor pressure is approximately exponential with a half-life of ∼9.4 h. These precursors are employed in a low pressure (5 Torr) horizontal, hot-wall, film growth reactor for growth of BaCaCuO(F) thin films on (110) LaAlO3 substrates. From the dependence of film deposition rate on substrate temperature and precursor partial pressure, the kinetics of deposition are shown to be mass-transport limited over the temperature range 350–650 °C at a 20 nm/min deposition rate. A ligand exchange process which yields volatile Cu(hfa)2 and Cu(hfa) (dpm) is also observed under film growth conditions. The MOCVD-derived BaCaCuO(F) films are postannealed in the presence of bulk Tl2Ba2CaCu2O8 at temperatures of 720–890 °C in flowing atmospheres ranging from 0–100% O2. The resulting Tl2Ba2CaCu2O8 films are shown to be epitaxial by x-ray diffraction and transmission electron microscopic (TEM) analysis with the c-axis normal to the substrate surface, with in-plane alignment, and with abrupt film-substrate interfaces. The best films exhibit a Tc = 105 K, transport-measured Jc= 1.2 × 105 A/cm2 at 77 K, and surface resistances as low as 0.4 mΩ (40 K, 10 GHz).

Sub-Surface Equilibration of Hydrogen with the a-Si:H Network Under Film Growth Conditions

1993 ◽  
Vol 297 ◽  
Author(s):  
ILSIN An ◽  
Y.M. Li ◽  
C.R. Wronski ◽  
R. W. Collins
Keyword(s):  
Hydrogen Diffusion ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Emission Rates ◽  
Near Surface ◽  
Kinetic Information ◽  
Reaction Processes ◽  
Surface Conversion

In this study we characterize hydrogen diffusion and reaction processes in the near-surface (top 200 Å) of a-Si:H that lead to network equilibration under standard conditions of plasma-enhanced chemical vapor deposition (PECVD). Real time spectroscopic ellipsometry (SE) is used to provide continuous kinetic information on the near-surface conversion of Si-Si to Si-H bonds during exposure of in situ-prepared films at 250°C to filament-generated atomic H. We have found that for optimum PECVD a-Si:H, the formation of additional Si-H bonds is limited by the capture of H at trapping sites, and the rapid diffusion process (D>10-14 cm2/s) by which H reaches the site is not detected optically. Deep trapping occurs at a rate of ∼10 3 s-1 under our filament conditions, estimated to generate ∼1020 cm-3 mobile H in the near-surface of the film. Finally, more than 1021 cm-3 additional H atoms are trapped with emission rates <2×10-7 s-1, suggesting trap depths >2.0 eV. Shallower traps are also detected at lower concentration.

Rapid Thermal Low Pressure Metalorganic Chemical Vapor Deposition of InP and Related Materials

1993 ◽  
Vol 300 ◽  
Author(s):  
A. Katz ◽  
A. Feingold
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Low Temperatures ◽  
Metalorganic Chemical Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Low Pressure ◽  
Growth Conditions ◽  
Metalorganic Chemical

ABSTRACTHigh quality InP and In0.53Ga0.67As undoped and Zn-doped layers were grown by means of rapid thermal low pressure metalorganic chemical vapor deposition (RTLPMOCVD) technique, using tertiarybutylphosphine (TBP) and tertiarybutylarsine (TBA), as the phosphorus and arsenic sources. The InP films were grown at a P:In ratios of about 75 and the InGaAs films were grown at a As:In ration of about 2, low temperatures at the range of 450-550°C, pressures it the range of 1-4 tons, and growth rates of 2-3 nm/sec. All the film growth conditions were optimized to yield defect-free layers with featureless morphology, which reflected at a minimum backscattering yield (Xmin) as low as 3.1% for the InP and 3.6% for the InGaAs. These films presented a good electrical properties, as well, with hole mobility of 4200 cm2/Vs for the undoped-InP layers and 75 cm2/Vs for the undoped-InGaAs layers.

The Effect of Substrate Orientation on the Properties of (Ga, Al)As Grown by Gas Source Molecular Beam Epitaxy

1988 ◽  
Vol 144 ◽  
Author(s):  
A. Sandhu ◽  
T. FUJII ◽  
H. Ando ◽  
H. Ishikawa ◽  
E. Miyauchi
Keyword(s):  
Growth Rate ◽  
Growth Conditions ◽  
Group V ◽  
Group Iii ◽  
Al Content ◽  
Gas Source ◽  
Compensation Ratio ◽  
Potential Applications ◽  
Si Doped ◽  
Gas Source Mbe

ABSTRACTWe have carried out the first systemmatic investigation on the effect of substrate temperature and arsenic partial pressure on the morphology, growth rate, and compensation ratio of Si-doped GaAs, and the Al content of AlxGa1−xAs grown on just-cut (100), (110), (111)A&B, (311)A&B orientated GaAs substrates by gas source MBE (GSMBE). Triethylgallium ( TEG, Ga(C2H5)3 ) and triethylaluminium ( TEA, Al(C2H5)3 ) were used as group III sources, and solid arsenic ( As4 ) and silicon as a group V and IV sources, respectively. The best GaAs mophology was obtained at relatively high temperatures and arsenic pressures. The A orientations were identified as ‘fast surfaces,’ with the GaAs growth rate being comparable to the (100) orientation. The B orientations were identified as ‘slow surfaces,’ with the GaAs growth rate being much less (approximately 50% for the (111)B orientation ) than on the (100) orientation. The least compensated Si-doped GaAs was grown on the (311)A orientated substrate. The Al content, x, (nominally x=0.27 for (100)) of AlxGas1−xAs grown on (110), (111)A&B, was less than 0.05 and not affected by the growth conditions. The Al content of epilayers grown on (311)A&B ranged between x=0.1 to 0.27, strongly depending on the growth temperature.These results show that using GSMBE we can selectively modifying a large range of (Ga,Al)As crystal properties. Potential applications include the selective growth and realisation of ultra-fine and planar structures and devices.

Characterization of Silicon-Nitride Film Growth by Remote Plasmaenhanced Chemical-Vapor Deposition (Rpecvd)

1993 ◽  
Vol 334 ◽  
Author(s):  
Zhong Lu ◽  
Yi Ma ◽  
Scott Habermehl ◽  
Gerry Lucovsky
Keyword(s):  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Nitride Film ◽  
Silicon Nitride Film ◽  
Flow Rates ◽  
Plasma Generation ◽  
Atom Source ◽  
Rate Ratios

AbstractWe have characterized RPECVD formation of Si-nitride films by relating the chemical bonding in the deposited films to the growth conditions. Gas flow rates for different N- and Si-atom source gases have been correlated with (i) the film stoichiometry, i.e., the Si/N ratio, and the (ii) the growth rate. N2 and NH3 were used as N-atom source gases, and were either delivered (i) up-stream through the plasmageneration tube, or (ii) down-stream. Different flow-rate ratios of NH3/SiH4 were found for deposition of stoichiometric Si-nitride films using up-stream or down-stream introduction of NH3. This is explained in terms of competition between excitation and recombination processes for the N-atom precursor species. Stoichiometric nitride films could not be obtained using the N2 source gas for (i) either up-stream or down-stream delivery, and (ii) for plasma powers up to 50 W. This is attributed to the higher relative binding energy of N-atoms in N2 compared to NH3, and to significant N-atom recombination at high N2 flow rates through the plasma generation region.

Sticking and Desorption Coefficients of As4 and As2 During Group V and Group III Controlled MBE Growth

1992 ◽  
Vol 263 ◽  
Author(s):  
Rouel Fernandez
Keyword(s):  
Activation Energy ◽  
Flux Ratio ◽  
Growth Conditions ◽  
High Energy ◽  
Controlled Growth ◽  
Sticking Coefficient ◽  
Group V ◽  
Mbe Growth ◽  
Group Iii ◽  
Sticking Coefficients

ABSTRACTReflection High Energy Electron Diffraction (RHEED) oscillations under arsenic and gallium-controlled Molecular Beam Epitaxy (MBE) growth conditions have been used to measure the sticking and desorption coefficients of As2 and As4. The coefficients are obtained from measurements of the arsenic incorporation rates. Comparisons are made with measurements obtained from desorption rates using modulated beam mass spectroscopy. The transition from gallium to arsenic-controlled growth is observed to occur after excess gallium atoms accumulate on the surface. The maximum intrinsic arsenic sticking coefficients occur when the maximum number of gallium atoms can be incorporated for a given arsenic flux. The intrinsic maximum arsenic sticking coefficients are found to be 0.75 and 0.50 for As2 and As4, respectively. During galliumcontrolled growth, the arsenic sticking coefficients are independent of substrate temperature as long as the sticking coefficient of gallium is equal to one. However, a temperature dependent maximum gallium-controlled arsenic sticking coefficient exists. It can be measured by the maximum Ga to As4 flux ratio that produces specular film surfaces. During gallium-controlled growth, the Ga to As flux ratios are shown to be equal to the gallium-controlled arsenic sticking coefficients. The activation energy for arsenic desorption during arsenic-controlled growth conditions was measured as -0.50 eV for independent As4 and As2 incident fluxes. During gallium-controlled growth with incident As4 fluxes, an activation energy for arsenic desorption of -0.70 eV was measured for the maximum gallium-controlled arsenic sticking coefficients.

Sign in / Sign up

Export Citation Format

Share Document