Integrated rotating-compensator polarimeter for real-time measurements and analysis of organometallic chemical vapor deposition

Phys. Status Solidi (c)

Aspnes

2008

We use a real‐time spectroscopic polarimeter integrated with an organometallic chemical vapor deposition system to investigate growth of GaP on Si, and particularly nanoscopically roughened (nr‐)Si. We find nanoroughening is necessary to increase the density of nucleation sites and decrease reactant mobility and thereby grow continuous films instead of widely spaced islands. The nrSi surfaces are more highly reactive to the trimethylgallium precursor than III‐V growth surfaces, leading to the appearance of metallic Ga if standard growth conditions are used in the initial phase of heteroepitaxy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

“…The integrated OMCVD/polarimeter is described elsewhere [9]. We used a chamber pressure of 20 Torr, with H 2 carrier gas at a flow rate of 10 slm.…”

Section: Methodsmentioning

confidence: 99%

Investigation of heteroepitaxy on nanoscopically roughened (001)Si by real‐time spectroscopic polarimetry

Liu

Phys. Status Solidi (c)

Aspnes

2008

“…15 The polarimeter operates at an angle of incidence of 70.2°and acquires relative-intensity ͑RI͒ and pseudodielectric function ͗͘ spectra at wavelengths from 230 to 840 nm at a 4 Hz rate, allowing real-time diagnostics on this time scale. 15 The polarimeter operates at an angle of incidence of 70.2°and acquires relative-intensity ͑RI͒ and pseudodielectric function ͗͘ spectra at wavelengths from 230 to 840 nm at a 4 Hz rate, allowing real-time diagnostics on this time scale.…”

Section: Methodsmentioning

confidence: 99%

Initial stages of GaP heteroepitaxy on nanoscopically roughened (001)Si

Liu

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

Aspnes

2007

GaP heteroepitaxy on Si(001): Correlation of Si-surface structure, GaP growth conditions, and Si-III/V interface structure J. Appl. Phys. 111, 083534 (2012); 10.1063/1.4706573Thickness inhomogeneities and growth mechanisms of GaP heteroepitaxy by organometallic chemical vapor deposition J.The authors report real-time spectroscopic-polarimetric determinations of the initial phase of GaP heteroepitaxy by organometallic chemical vapor deposition on nanoscopically roughened ͑NR͒ ͑001͒Si substrates, where polarimetry measurements are also used to quantify roughness. The authors compare the results with analogous data for GaP homoepitaxy and the initial phase of GaP heteroepitaxy on ͑001͒GaAs. The large density of nucleation sites on NRSi significantly improves film continuity relative to nonroughened vicinal ͑001͒Si substrates, but conditions that are typically used to grow GaP on ͑001͒III-V surfaces generate metallic Ga, indicating that NRSi is more efficient at decomposing trimethylgallium than either GaP or GaAs.

“…The system, including the integrated RTSE/OA spectrometer, has been described in detail elsewhere. 6,7 For the work discussed here the carrier gas was tank H 2 used without filtering. Precursors were TMG, TMSb, and arsine (AsH 3 ), with the AsH 3 being used to ensure stability of the ͑001͒GaAs substrates during cleaning and to grow buffer layers prior to GaSb heteroepitaxy.…”

Section: Methodsmentioning

confidence: 99%

“…Our experiments are performed with our OMCVD reactor with integrated single-beam ellipsometer/polarimeter/optical-anisotropy spectrometer, 6,7 which returns 1024-pixel data from 240 to 840 nm at rates up to 5 Hz. The real-time spectroscopic ellipsometry ͑RTSE͒ data provide information about the presence or absence of overlayers and film thicknesses and compositions, while the anisotropy data nominally provide information about surface termination and therefore chemical bonding, all on the picometer scale.…”

Section: Introductionmentioning

confidence: 99%

Real-time characterization of GaSb homo- and heteroepitaxy

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

Flock

Asar

et al. 2004

Self Cite

We examine the homo- and heteroepitaxial growth of moderately thick (∼700 nm) layers of GaSb with the objectives of optimizing growth conditions and determining the initial phase of heteroepitaxy on (001)GaAs. Real-time spectroscopic ellipsometry (RTSE) data show that the (001)GaSb surface degrades immediately in excess trimethylgallium (TMG), but both (001)GaSb and As-terminated (001)GaAs surfaces are stable in trimethylantimony (TMSb). The surface-dimer contribution to the optical-anisotropy (OA) signal of (001)GaSb is small and generally masked by structural (roughness) effects, hence it is not useful for determining surface stoichometry. However, we show that laser light scattering (LLS) data do allow the V/III ratio to be fine-tuned during growth to minimize macroscopic roughness. TEM micrographs show that our GaSb/GaAs heterointerface is relatively defect-free except for the necessary local accommodation of lattice mismatch. The initial phase of heteroepitaxy on (001)GaAs occurs here as a coexistence of separate regions of GaAs and GaSb.