MBE Growth of Epitaxial Calcium Fluoride on Silicon

1985 ◽  
Vol 54 ◽  
Author(s):  
L. J. Schowalter ◽  
R. W. Fathauer

ABSTRACTThe growth of an epitaxial insulator such as CaF2. on Si substrates and ita subsequent overgrowth with epitaxial sen iconduct ors have a number of important applications in the electronics industry. In addition, it presents a unique opportunity to study an insulator/semiconductor interface under controlled conditions. We have studied the growth of epitaxial CaF. on Si substrates and their subsequent overgrowth with Si or Ge under various conditions. While epitaxial growth of CaF2, (which has an fee lattice structure as does Si) can be obtained on (100), (110) and (111) oriented Si substrates, the best quality crystal growth and surface morphology is obtained on (111) substrates as the CaF. (111) surface has the lowest free energy. Atomic steps on the original Si substrate surface are shown to have a detrimental effect on the epitaxial growth of CaF2. I-V measurements on the epitaxial (111) films show that the intrinsic breakdown field strength exceeds 2 MV/cm, however, high-field induced ionization can cause thermal breakdown at lower voltages. C-V measurements typically show ∼1012 states/cm in the Si band gap as grown. However, it is possible to reduce this number to less than 10 by annealing procedures after growth.

1988 ◽  
Vol 126 ◽  
Author(s):  
H. Noge ◽  
H. Kano ◽  
M. Hashimoto ◽  
I. Igarashi

ABSTRACTGaAs layers free of antiphase domains (APD's) have been grown by molecular beam epitaxy (MBE) on nominally (001)-oriented Si substrates. This is achieved by preheating the substrates at 950°C over 60 min or at 1000°C over 5 min in an ultrahigh vacuum. The maximum Hall mobility at 293 K is 5300 cm2/Vs for the APD-free GaAs layer doped with Si at a concentration of 2×1016 cm−3. Selective epitaxial growth of GaAs has been carried out on a Si substrate pattrened with SiO2, which was formed by wet O2 oxidation. By choosing an appropriate thickness of the SiO2 layer, thzxcSe warpage of wafers can be reduced to zero. While single-crystalline GaAs is grown on Si-exposed areas, highly-resistive (p ≧ 105 Ωcm) poly-crystalline GaAs is deposited on SiO2. This technique has been successfully applied for the device isolation of modulation-doped FET's (MODFET's, HEMT's, etc.) on Si without mesa-etching. The transconductance of the MODFET with a 3 μm-long gate reaches 88 mS/mm at 293 K.


1988 ◽  
Vol 116 ◽  
Author(s):  
H. Noge ◽  
H. Kano ◽  
M. Hashimoto ◽  
I. Igarashi

AbstractGaAs layers free of antiphase domains (APD's) have been grown by molecular beam epitaxy (MBE) on nominally (001)-oriented Si substrates. This is achieved by preheating the substrates at 950 °C over 60 min or at 1000 °C over 5 min in an ultrahigh vacuum. The maximum Hall mobility at 293 K is 5300 cm2 /Vs for the APD-free GaAs layer doped with Si at a concentration of 2×1016 cm−3 . Selective epitaxial growth of GaAs has been carried out on a Si substrate pattrened with SiO2, which was formed by wet O2 oxidation. By choosing an appropriate thickness of the SiO2 layer, the warpage of wafers can be reduced to zero. While single-crystalline GaAs is grown on Si-exposed areas, highly-resistive (ρ ≧ 105 Ωcm) poly-crystalline GaAs is deposited on SiO2 . This technique has been successfully applied for the device isolation of modulation-doped FET's (MODFET's, HEMT's, etc.) on Si without mesa-etching. The transconductance of the MODFET with a 3 µm-long gate reaches 88 mS/mm at 293 K.


1994 ◽  
Vol 358 ◽  
Author(s):  
K. Dovidenko ◽  
S. Oktyabrsky ◽  
J. Narayan ◽  
M. Razeghi

ABSTRACTThe microstructural characteristics of wide band gap semiconductor, hexagonal A1N thin films on Si(100), (111), and sapphire (0001) and (10ī2) were studied by transmission electron microscopy (TEM) and x-ray diffraction. The films were grown by MOCVD from TMA1 + NH3 + N2 gas mixtures. Different degrees of film crystallinity were observed for films grown on α-A12O3 and Si substrates in different orientations. The epitaxial growth of high quality single crystalline A1N film on (0001) α-Al2O3 was demonstrated with a dislocation density of about 2*10 10cm−2 . The films on Si(111) and Si(100) substrates were textured with the c-axis of A1N being perpendicular to the substrate surface.


1992 ◽  
Vol 280 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tana ◽  
P. L. Smith ◽  
G. E. Mcguire

ABSTRACTThe mechanism of formation of epitaxial CoSi2 film on (001) Si substrate, produced using sequentially deposited Ti-Co bimetallic layer source materials for which Ti was deposited onto the Si substrates first, has been studied by observing the Co silicide formation processes and structures in samples prepared by isochronal annealing and by isothermal annealing. The results demonstrated that, in leading to epitaxial CoSi2 film formation, Ti has played two roles. It has served as a barrier material to Co atoms and thus preventing Co2Si from forming. More importantly, it has allowed nucleation and growth of epitaxial-CoSi2 to dominate the Co silicide film formation process, apparently because it has served as a cleanser to remove native oxide from the Si substrate surface.


Author(s):  
J.H. Mazur ◽  
J. Washburn ◽  
T. Henderson ◽  
J. Klem ◽  
W.T. Masselink ◽  
...  

Possibility of growth of epitaxial lll-V (GaAs, InP, GaP, etc.) compound semiconductors on nonpolar substrates (Ge,Si) is of considerable interest from the view point of monolithic integration of lll-V optoelectronic and Si electronic devices. The growth of GaAs and AIGaAs layers on Si substrates is additionally attractive because of good mechanical strength and low cost of Si substrates. However, a principal difficulty in growing polar semiconductors on nonpolar substrates is that there are no preferential bonding sites for cations and anions in the first layer of growth, which can result in antiphase boundaries (APB’s) in addition to defects due to misfit (∼4% for GaAs on Si).In this work GaAs layers were grown on (100) Si substrates using procedures described elsewhere. The MBE growth started from a first deposition of As as a prelayer on the Si substrate followed by GaAs growth at 580°C. Cross-sectional TEM specimens were prepared using the same procedures as reported earlier for the case of Si-SiO2 cross-sections.


1993 ◽  
Vol 8 (6) ◽  
pp. 1361-1367 ◽  
Author(s):  
Cheol Seong Hwang ◽  
Hyeong Joon Kim

ZrO2 thin films were deposited at 1 atm on Si substrates by oxidation-assisted thermal decomposition of zirconium-trifluoroacetylacetonate in the temperature range of 300–615 °C. Above a deposition temperature of 400 °C, the deposited thin films have a columnar grain structure, where each grain is perpendicular to the substrate surface with a c-axis preferred crystallographic orientation, and have poor electrical characteristics as a dielectric thin film. But the thin film deposited at 350 °C has a fine equiaxed microcrystalline structure and has superior electrical characteristics of a breakdown field of 1 MV/cm and a relative dielectric constant of 27.


2011 ◽  
Vol 679-680 ◽  
pp. 801-803
Author(s):  
Ji Sheng Han ◽  
Sima Dimitrjiev ◽  
Li Wang ◽  
Alan Iacopi ◽  
Qu Shuang ◽  
...  

Gallium nitrides are primarily used for their excellent light emission properties. GaN LEDs are mostly grown on foreign substrates, essentially sapphire and SiC, but more recently, also on Si substrates. In this paper, we will demonstrate that the high structural quality of InGaN/GaN multiple quantum wells can be deposited on 3C-SiC/Si (111) substrate using MOCVD. This demonstrates that 3C-SiC/Si is a promising template for the epitaxial growth of InGaN/GaN multiple quantum wells for LEDs.


2011 ◽  
Vol 679-680 ◽  
pp. 107-110
Author(s):  
Tae Woo Lee ◽  
Im Gyu Yeo ◽  
Byoung Chul Shin ◽  
Won Jae Lee ◽  
Mi Seon Park ◽  
...  

We adopted HMDS(Hexamethyledisilane) as a SiC(Silicon carbide) source material for epitaxial growth of 3C-SiC on Si substrate. Various growth profiles were investigated to optimize hetero-epitaxial growth of 3C-SiC layers. We also focused on the homogeneous film deposition of 3C-SiC on Si by employing two susceptor shapes, flat and tilted susceptors, to control a thickness of the boundary layer formed on the Si substrate. Fringe color patterns were observed on 3C-SiC layer on Si and hence it was easy to characterize the film uniformity by analyzing this color. 3C-SiC epitaxial layers were systematically analyzed by an optical microscope, a Raman spectroscopy, a SEM and an XRD.


2001 ◽  
Vol 688 ◽  
Author(s):  
Norimasa Nukaga ◽  
Takayuki Watanabe ◽  
Tomohiro Sakai ◽  
Toshimasa Suzuki ◽  
Yuji Nishi

AbstractBismuth layered structured ferroelectrics (BLSF) thin films with different number of octahedron number (m-number) were prepared by MOCVD and directly crystallized on the substrates. Directly-crystallized SrBi2Ta2O9 (SBT) (m=2) films on a (111) Pt/Ti/SiO2/Si substrate were ascertained to have a strong (103) one-axis orientation by the X-ray reciprocal space mapping and to be hetero-epitaxially grown on the (111) Pt grains by the TEM observation. Moreover, directly crystallized Bi2VO5.5 (m=1) and Bi4Ti3O12 (m=3) films deposited on the same substrate showed (102) and (104) one-axis preferred orientations, respectively. These orientations are basically the equal ones with SBT (103) orientation because the tilting angle of c-axis from the substrate surface is also about 55°. Therefore, the direct crystallization is one of the important key techniques for orientation control of BLSF films. Moreover, the directly crystallized SBT film deposited on a (111) Ir/TiOx/SiO2/Si substrate at 570 °C by ECR-MOCVD exhibited (103) one-axis orientation, which also originated from the local epitaxial growth on (111)-oriented Ir grains. The remanent polarization (2Pr), and the coercive field (Ec) of this film were 16.1 μC/cm2 and 83 kV/cm at an applied electric field of 360kV/cm, respectively. This Pr value is about 88% of the expected value of (103)-oriented SBT film from both the Pr values of the (116) and (001)-oriented epitaxial films and detailed crystal analysis.


Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1904
Author(s):  
Marta Sobanska ◽  
Núria Garro ◽  
Kamil Klosek ◽  
Ana Cros ◽  
Zbigniew R. Zytkiewicz

The growth of GaN nanowires having a polar, wurtzite structure on nonpolar Si substrates raises the issue of GaN nanowire polarity. Depending on the growth procedure, coexistence of nanowires with different polarities inside one ensemble has been reported. Since polarity affects the optical and electronic properties of nanowires, reliable methods for its control are needed. In this work, we use Kelvin probe force microscopy to assess the polarity of GaN nanowires grown by plasma-assisted Molecular Beam Epitaxy on Si(111) substrates. We show that uniformity of the polarity of GaN nanowires critically depends on substrate processing prior to the growth. Nearly 18% of nanowires with reversed polarity (i.e., Ga-polar) were found on the HF-etched substrates with hydrogen surface passivation. Alternative Si substrate treatment steps (RCA etching, Ga-triggered deoxidation) were tested. However, the best results, i.e., purely N-polar ensemble of nanowires, were obtained on Si wafers thermally deoxidized in the growth chamber at ~1000 °C. Interestingly, no mixed polarity was found for GaN nanowires grown under similar conditions on Si(111) substrates with a thin AlOy buffer layer. Our results show that reversal of nanowires’ polarity can be prevented by growing them on a chemically uniform substrate surface, in our case on clean, in situ formed SiNx or ex situ deposited AlOy buffers.


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