GaP Epilayers Research Articles

Growth and Characterization of Si-GaP and Si-GaP-Si Heterostructures

AbstractThe low temperature epitaxial growth of Si / GaP / Si heterostructures is investigated with the aim using GaP as a dielectric isolation layer for Si circuits. GaP layers have been deposited on Si(100) surfaces by chemical beam epitaxy (CBE) using tertiarybutyl phosphine (TBP) and triethylgallium (TEG) as source materials. The influence of the cleaning and passivation of the GaP surface has been studied in-situ by AES and LEED, with high quality epitaxial growth proceeding on vicinal GaP(100) substrates. Si / GaP / Si heterostructures have been investigated by cross sectional high resolution transmission electron microscope (HRTEM) and secondary ion mass spectroscope (SIMS). These methods reveal the formation of an amorphous SiC interlayer between the Si substrate and GaP film due to diffusion of carbon generated in the decomposition of the metalorganic precursors at the surface to the GaP/Si interface upon prolonged growth (layer thickness > 300Å). The formation of twins parallel to {111} variants in the GaP epilayer are extended into the subsequently grown Si film with minor generation of new twins.

MOMBE growth of P-based III–V semiconductors and its photo-enhancement at low temperatures

GaP and AlGaP epilayers grown at temperatures ranging from 420 to 500°C had smooth surfaces and streaky RHEED patterns. GaP epilayers showed quite sharp peaks of isoelectronic traps due to nitrogen atoms and its phonon replica in the photoluminescence spectrum at 11 K. The decomposition of group-III sources of TEGa and TEAl limits the growth rates of GaP, AlP and AlGaP at lower substrate temperatures (<390°C). The growth rate of GaP epitaxial layers was efficiently enhanced by N 2-laser irradiation with a laser power of as low as 70 μJ/pulse at lower substrate temperatures.

LPE Lateral Overgrowth of GaP

Epitaxial lateral overgrowth (ELO) of GaP on SiO2-coated (111)B or (111)A GaP substrates was carried out successfully by LPE. It was found that the ELO of GaP showed dependency on seed orientation similar to that of GaAs. However, a pronounced asymmetry of lateral growth in [2̄11] and [21̄1̄] orientations was found. Monomolecular growth steps on the ELO layer have been observed by a Nomarski differential interference contrast microscope equipped with an image processor without decoration. Nitrogen doping was performed, and its nonuniform distribution was investigated by a fluorescence microscope and spatially resolved photoluminescence. From the nonuniformity, an understanding of the ELO mechanism was derived. It was found that the epilayer had a much lower dislocation density than that in a substrate. It was concluded that wide and extremely flat GaP epilayers with high quality can be obtained by the ELO technique.

Quality improvement of metalorganic chemical vapor deposition grown GaP on Si by AsH3 preflow

GaP epilayers are grown on Si substrates after AsH3 preflow. Electron beam induced current observation and double-crystal x-ray diffraction show that the AsH3 preflow drastically improves crystalline quality of GaP epilayers. The full width at half-maximum of the (400) reflection obtained from 4.8 μm GaP is as small as 115 arcseconds. Secondary ion mass spectroscopy shows that As atoms accumulate at the GaP/Si interfaces, playing an important role in preventing Si outdiffusion into the GaP epilayers.

The growth of a GaP epilayer on Si substrates by metallorganic CVD: Yan-kuin Su,J Phys D : Appl Phys, 15 (11), 1982, 2325–2330

The growth of a GaP epilayer on Si substrates by metallorganic CVD: Yan-kuin Su,J Phys D : Appl Phys, 15 (11), 1982, 2325–2330

The growth of a GaP epilayer on Si substrates by metallorganic CVD

Single crystal GaP epilayers can be grown successfully by metallorganic vapour phase epitaxy on Si substrates by thermal decomposition of a gas mixture of triethylgallium (TEG) and phosphine (PH3). The optimum growth temperature and the optimum mole ratio of P and Ga were 660 degrees C and 13 to 1, respectively. The as-grown GaP layer was n-type. The concentration and mobility of GaP layers at room temperature were in the range 3*1016-8.5*1016 cm-3 and 50-100 cm2 V-1 s-1, respectively. I-V and C-V characteristics of this heterojunction device were measured. The leakage current was a few tenths of a mu A and the breakdown voltage was 12 V. A linear relationship of C-2.08 and voltage can be obtained. There is a wide wavelength range of photo-response (from 0.5 mu m to 1.2 mu m) for this diode. The dependence of open-circuit voltage and short-circuit current on light intensity were also measured.