Characterization of LP-MOCVD Grown (Al, Ga)As/GaAs Heterostructures by Photoluminescence: Single Heterojunction and Inadvertent Quantum Wells

Zemon, S.; Black, John B.; Norris, P.; Lee, J.; Lambert, G.

doi:10.1143/jjap.23.l925

Cited by 4 publications

(2 citation statements)

References 4 publications

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“…Such precursors are often delivered using a carrier gas that is passed through either a bubbler, i.e., a vessel with a dip tube, or a vapor draw ampoule, i.e., a vessel with no dip tube in which the gas-in and gas-out ports open directly into the ampoule headspace. A lack of adequate control can result in an irreproducible amount of entrained precursor, and the negative impacts of such variations on film and device properties have been widely reported [1][2][3][4][5][6][7][8][9][10]. Several factors can contribute to an inadequate level of control, including the design of the gas manifold [5,7,8,11], the design of the ampoule temperature-control system [12], the gas flow path in the ampoule [13][14][15], evaporative/sublimative cooling of the precursor in the ampoule [16,17], and the changing surface area of solid precursors in the ampoule 2 https://doi.org/10.6028/jres.124.005 (due to sublimation and subsequent recrystallization) [14,15,18].…”

Section: Introductionmentioning

confidence: 99%

Apparatus for Characterizing Gas-Phase Chemical Precursor Delivery for Thin Film Deposition Processes

Maslar

Kimes

Sperling

2019

J. RES. NATL. INST. STAN.

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Thin film vapor deposition processes, e.g., chemical vapor deposition, are widely used in high-volume manufacturing of electronic and optoelectronic devices. Ensuring desired film properties and maximizing process yields require control of the chemical precursor flux to the deposition surface. However, achieving the desired control can be difficult due to numerous factors, including delivery system design, ampoule configuration, and precursor properties. This report describes an apparatus designed to investigate such factors. The apparatus simulates a single precursor delivery line, e.g., in a chemical vapor deposition tool, with flow control, pressure monitoring, and a precursor-containing ampoule. It also incorporates an optical flow cell downstream of the ampoule to permit optical measurements of precursor density in the gas stream. From such measurements, the precursor flow rate can be determined, and, for selected conditions, the precursor partial pressure in the headspace can be estimated. These capabilities permit this apparatus to be used for investigating a variety of factors that affect delivery processes. The methods of determining the pressure to (1) calculate the precursor flow rate and (2) estimate the headspace pressure are discussed, as are some of the errors associated with these methods. While this apparatus can be used under a variety of conditions and configurations relevant to deposition processes, the emphasis here is on low-volatility precursors that are delivered at total pressures less than about 13 kPa downstream of the ampoule. An important goal of this work is to provide data that could facilitate both deposition process optimization and ampoule design refinement.

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Section: Introductionmentioning

confidence: 99%

Apparatus for Characterizing Gas-Phase Chemical Precursor Delivery for Thin Film Deposition Processes

Maslar

Kimes

Sperling

2019

J. RES. NATL. INST. STAN.

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“…Process optimization can depend critically on precise control of the precursor flux to the deposition surface, and the negative impact of metalorganic precursor concentration variations on film and device properties have been widely reported. 1–11 Schemes for improving control of precursor delivery in vapor deposition processes fall within two main categories: enhanced precursor delivery system design; 5,9,12–18 and closed loop control of precursor flux. 2–4,6,19–25 Metrologies that provide the time-dependent precursor concentration can contribute to both methods.…”

Section: Introductionmentioning

confidence: 99%

Nondispersive Infrared Gas Analyzer for Vapor Density Measurements of a Carbonyl-Containing Organometallic Cobalt Precursor

et al. 2017

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A nondispersive infrared (NDIR) gas analyzer was demonstrated for measuring the vapor-phase density of the carbonyl-containing organometallic cobalt precurso μ-η-(Bu-acetylene) dicobalthexacarbonyl (CCTBA). This sensor was based on direct absorption by CCTBA vapor in the C≡O stretching spectral region and utilized a stable, broadband IR filament source, an optical chopper to modulate the source, a bandpass filter for wavelength isolation, and an InSb detector. The optical system was calibrated by selecting a calibration factor to convert CCTBA absorbance to a partial pressure that, when used to calculate CCTBA flow rate and CCTBA mass removed from the ampoule, resulted in an optically determined mass that was nominally equal to a gravimetrically-determined mass. In situ Fourier transform infrared (FT-IR) spectroscopy was performed simultaneously with the NDIR gas analyzer measurements under selected conditions in order to characterize potential spectroscopic interferences. Interference due to CO evolution from CCTBA was found to be small under the flow conditions employed here. A CCTBA minimum detectable molecular density as low as ≈3 × 10cm was calculated (with no signal averaging and for a sampling rate of 200 Hz). While this NDIR gas analyzer was specifically tested for CCTBA, it is suitable for characterizing the vapor delivery of a range of carbonyl-containing precursors.

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OMVPE growth of 660 nm AIGaAs double heterojunction LEDs

Kellert

Moon

1986

J. Electron. Mater.

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Characterization of LP-MOCVD Grown (Al, Ga)As/GaAs Heterostructures by Photoluminescence: Single Heterojunction and Inadvertent Quantum Wells

Cited by 4 publications

References 4 publications

Apparatus for Characterizing Gas-Phase Chemical Precursor Delivery for Thin Film Deposition Processes

Apparatus for Characterizing Gas-Phase Chemical Precursor Delivery for Thin Film Deposition Processes

Nondispersive Infrared Gas Analyzer for Vapor Density Measurements of a Carbonyl-Containing Organometallic Cobalt Precursor

OMVPE growth of 660 nm AIGaAs double heterojunction LEDs

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