• Title/Summary/Keyword: GaAs(100) Surface

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GaAs Epilayer Growth on Si(100) Substrates Cleaned by As/Ga Beam and Its RHEED Patterns (As과 Ga 빔 조사에 의해 세척된 Si(100) 기판 위에 GaAs 에피층 성장과 RHEED 패턴)

  • Yim, Kwang-Gug;Kim, Min-Su;Leem, Jae-Young
    • Journal of the Korean institute of surface engineering
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    • v.43 no.4
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    • pp.170-175
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    • 2010
  • The GaAs epitaxial layers were grown on Si(100) substrates by molecular beam epitaxy(MBE) using the two-step method. The Si(100) substrates were cleaned with different surface cleaning method of vacuum heating, As-beam, and Ga-beam at the substrate temperature of $800^{\circ}C$. Growth temperature and thickness of the GaAs epitaxial layer were $800^{\circ}C$ and 1 ${\mu}m$, respectively. The surface structure and epitaxial growth were observed by reflection high-energy electron diffraction(RHEED) and scanning electron microscope(SEM). Just surface structure of the Si(100) substrate cleaned by Ga-beam at $800^{\circ}C$ shows double domain ($2{\times}1$). RHEED patterns of the GaAs epitaxial layers grown on Si(100) substrates with cleaning method of vacuum heating, As-beam, and Ga-beam show spot-like, ($2{\times}4$) with spot, and clear ($2{\times}4$). From SEM, it is found that the GaAs epitaxial layers grown on Si(100) substrates with Ga-beam cleaning has a high quality.

Effects of Substrate Cleaning on the Properties of GaAs Epilayers Grown on Si(100) Substrate by Molecular Beam Epitaxy (분자선에피택시에 의해 Si (100) 기판 위에 성장한 GaAs 에피층의 특성에 대한 기판 세척효과)

  • Cho, Min-Young;Kim, Min-Su;Leem, Jae-Young
    • Journal of the Korean Vacuum Society
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    • v.19 no.5
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    • pp.371-376
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    • 2010
  • The GaAs epitaxial layers were grown on Si(100) substrates by molecular beam epitaxy (MBE) using the two-step method. The Si(100) substrates were cleaned with three different surface cleaning methods of vacuum heating, As-beam exposure, and Ga-beam deposition at the substrate temperature of $800^{\circ}C$ in the MBE growth chamber. Growth temperature and thickness of the GaAs epitaxial layer were $800^{\circ}C$ and $1{\mu}m$, respectively. The surface structure and properties were investigated by reflection high-energy electron diffraction (RHEED), AFM (Atomic force microscope), DXRD (Double crystal x-ray diffraction), PL (Photoluminescence), and PR (Photoreflectance). From RHEED, the surface structure of GaAs epitaxial layer grown on Si(100) substrate with Ga-beam deposition is ($2{\times}4$). The GaAs epitaxial layer grown on Si(100) substrate with Ga-beam deposition has a high quality.

Facet Growth of InGaAs on GaAs(100) by Chemical Beam Epitaxy Using Unprecracked Monoethylarsine (GaAs(100) 기판에 사전 열분해하지 않은 Monoethylarsine을 사용하는 Chemical Beam Epitaxy방법에 의한 InGaAs박막의 Facet 성장에 관한 연구)

  • 김성복;박성주;노정래;이일항
    • Journal of the Korean Vacuum Society
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    • v.5 no.3
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    • pp.199-205
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    • 1996
  • InGaAs eqitaxial layers have been selectively grown on patterned GaAs(100) substrates by chemical beam epitaxy (CBE) using triethylgallium (TEGa), trimethylindium (TMIn), and unprecracked monoethylarsine (MEAs). Facet growth of InGaAs epilayers has also been investigated at the various growth temperatures and Si4N4 dielectric pattern directions. In [011] jirection of mask, the change from (311), (377) and (111) facets to (311) facet with increasing growth temperature was observed. In [011] direction, however, the change from (011) and (111) facets to (111) facet with increasing growth temperature was observed. These results are attributed to the sidewall growth caused by different surface migration lengths of reactants. The formation of U-shaped (100) top surface is also discussed in terms of dangling bond model.

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Crystallinity and Internal Defect Observation of the ZnTe Thin Film Used by Opto-Electronic Sensor Material (광소자로 사용되는 ZnTe박박의 결정성에 따른 결함 관찰)

  • Kim, B.J.
    • Journal of the Korean institute of surface engineering
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    • v.35 no.5
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    • pp.289-294
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    • 2002
  • ZnTe films have been grown on (100) GaAs substrate with two representative problems. The one is lattice mismatch, the other is thermal expansion coefficients mismatch of ZnTe /GaAs. It claims here, the relationship of film thickness and defects distribution with (100) ZnTe/GaAs using hot wall epitaxy (HWE) growth was investigated by transmission electron microscopy (TEM). It analyzed on the two-sort side using TEM with cross-sectional transmission electron microscopy (XTEM) and high-resolution electron microscopy (HREM). Investigation into the nature and behavior of dislocations with dependence-thickness in (100) ZnTe/ (100) GaAs hetero-structures grown by transmission electron microscopy (TEM). This defects range from interface to 0.7 $\mu\textrm{m}$ was high density, due to the large lattice mismatch and thermal expansion coefficients. The defects of low density was range 0.7$\mu\textrm{m}$~1.8$\mu\textrm{m}$. In the thicker range than 1.8$\mu\textrm{m}$ was measured hardly defects.

Characteristics of MOVPE Grown HgCdTe on GaAs and CdZnTe Substrates (GaAs 및 CdZnTe기판위에 MOVPE 법으로 성장된 HgCdTe 박막의 특성)

  • 김진상;서상희
    • Korean Journal of Crystallography
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    • v.12 no.3
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    • pp.171-176
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    • 2001
  • HgCdTe films were grown on the (100). (111), (211) CdZnTe, and (100) GaAs substrates by metal organic chemical vapor epitaxy. We have investigated the surface morphology, electrical properties, crystalline qualities, and composition of HgCdTe with substrates orientation. Three dimensional facet growth was occurred on (111) CdZnTe substrate. The crystalline quality of HgCdTe on (100) CdZnTe was superior to that of HgCdTe on (100) GaAs. FWHM values of double crystal x-ray diffraction of HgCdTe on (100) CdZnTe and (100) GaAs were 55 and 125arcsec, respectively. HgCdTe on GaAs substrate showed n-type conductivity with high mobility, however, HgCdTe on CdZnTe showed p-type conductivity with carrier concentration of higher than 10/sup 16/㎤.

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The Passivation of GaAs Surface by Laser CVD

  • Sung, Yung-Kwon;Song, Jeong-Myeon;Moon, Byung-Moo;Rhie, Dong-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.12S
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    • pp.1242-1247
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    • 2003
  • In order to passivate the GaAs surface, silicon-nitride films were fabricated by using laser CVD method. SiH$_4$ and NH$_3$ were used to obtain SiN films in the range of 100∼300$^{\circ}C$ on p-type (100) GaAs substrate. To determine interface characteristics of the metal-insulator-GaAs structure, electrical measurements were performed such as C-V curves and deep level transient spectroscopy (DLTS). The results show that the hysteresis was reduced and interface trap density was lowered to 1,012 ∼ 1,013 at 100 ∼ 200$^{\circ}C$. According to the study of surface leakage current, the passivated CaAs has less leakage current compared to non-passivated substrate.

An Investigation of Selective Etching of GaAs to Al\ulcornerGa\ulcornerAs Using BCI$_3$SF\ulcorner Gas Mixture in ECR Plasma (ECR 플라즈마에서 $BCI_3/SF_6$ 혼합 가스를 이용한 $Al_{0.25}Ga_{0.75}As$에 대한 GaAs의 선택적 식각에 대한 연구)

  • 이철욱;이동율;손정식;배인호;박성배
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.6
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    • pp.447-452
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    • 1998
  • The selective dry etching of GaAs to Al\ulcornerGa\ulcornerAs using $BCI_3/SF_6$ gas mixture in electron cyclotron resonance(ECR) plasma is investigated. A selectivity of GaAs to AlGaAs of more than 100 and maximum etch rate of GaAs are obtained at a gas ratio $SF_6/BCI_3+SF_6$ of 25%. We verified the formation of $AlF_3$ on $Al_{0.25}Ga_{0.75}As$from the Auger spectra which enhanced the etch selectivity. In order to investigate surface damage of AlGaAs caused by ECR plasma, we performed a low temperature photoluminescence(PL) measurement as a function of RF power. As the RF power. As the RF power increases, the PL intensity decreases monotonically from 50 to 100 Wand then repidly decreases until 250 W. This behavior is due to surface damage by plasma treatment. This dry etching technique using $BCI_3/SF_6$ gas mixture in ECR plasma is suitable for gate recess formation on the GaAs based pseudomorphic high electron mobility transistor(PHEMT)

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A Study on Photoreflectance of n-GaAs Treated with$Se/NH_4OH$ Solution ($Se/NH_4OH$용액으로 처리시킨 n-GaAs의 Photoreflectance에 관한 연구)

  • 김근형;김인수;이정열;이동건;배인호;박성배
    • Electrical & Electronic Materials
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    • v.10 no.6
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    • pp.555-561
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    • 1997
  • The passivation of n-GaAs(100) surface has investigated by photoreflectance(PR). The surface of the sample was treated with the 0.001 N solution Se/NH$_4$OH. After the surface treatment, the samples were annealed between 400 to $700^{\circ}C$ in a $N_2$atmosphere for 10 min. The intensity of PR signal and period of Franz-Deldysh oscillation(FKO) gradually decreased as the annealing temperature increased. The surface electric field(E$_{s}$) of the sample annealed at $600^{\circ}C$ is obtained 1.34$\times$10$^{5}$ V/cm. This value is 1.97 times less than that of unannealed sample. It has found that the passivation of surface occurred when the surface of the sample had been treated with Se/NH$_4$OH solution and annealed from 500 to $600^{\circ}C$. This result could be due to activation of elemental Se on the surface. It has also found that the elemental Se of the surface diffused about 100 $\AA$ into the bulk GaAs when Se-treated sample was annealed at $600^{\circ}C$.>.

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Morphological Evolution of GaAs(100) Surfaces during Inductively Coupled Plasma Etching at Floating Potential (Floating potential에서 유도결합 플라즈마 식각에 의한 GaAs(100) 표면의 형태 변화)

  • Lee, Sang-Ho
    • Journal of the Korean Vacuum Society
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    • v.16 no.1
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    • pp.15-22
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    • 2007
  • We present the morphological evolution at different source powers in the ion-enhanced etching of GaAs(100) in $BCl_3-Cl_2$ plasma. With little ion bombardment at floating potential, the surface develops <110< ridges and {111} facets, as it does in purely chemical etching. The morphology develops in less than 1 minute and grows bigger over time. The etched surfaces show different morphologies at different source powers with constant pressures of gases. Lowe. source power (100 W) produces poorly developed crystallographic surfaces while higher source power (900 W) produces well developed crystallographic surfaces. This is attributed to the availability of excited reactive species(chlorine atoms) depending on source powers. With more concentration of the reactive species at higher source powers, the surface of GaAs(100) would be a surface that is expected from thermodynamics while the surface morphology would be determined by sputtering in the lack of reactive species. Statistical analysis of the surfaces, based on scaling theory, revealed two spatial exponents: one(smaller than one) is formed by atomic scale mechanisms, the other(larger than one) is formed by larger scale mechanisms which is believed to develop facets.

Morphology Evolution of GaAs(100) Surfaces during Inductively Coupled Plasma Etching at Biased Potential (유도결합 플라즈마 식각시 bias에 의한 GaAs(100) 표면의 형태 변화)

  • Lee, Sang-Ho
    • Journal of the Korean Vacuum Society
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    • v.16 no.4
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    • pp.250-261
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    • 2007
  • We present the morphological evolution at different source powers in the ion-enhanced etching of GaAs(100) in $BCl_3-Cl_2$ plasma. With little ion bombardment at floating potential, the surface develops <110> ridges and {111} facets, as it does in purely chemical etching. Higher source power (900 W) produces well developed crystallographic surfaces while lower source power (100 W) produces poorly developed crystallographic surfaces. This is attributed to the availability of excited reactive species (chlorine atoms) depending on source powers. With more concentration of the reactive species at higher source powers, the surface of GaAs(100) would be a surface that is expected from thermodynamics while the surface morphology would be determined by sputtering in the lack of reactive species. Statistical analysis of the surfaces, based on scaling theory, revealed two spatial exponents: one (smaller than one) is formed by atomic scale mechanisms, the other (larger than one) is formed by larger scale mechanisms which is believed to develop facets. When samples are biased, the surfaces experienced bombardment resulting in suppression of ridge formation at high source power and islands formation at low source power.