The Microstructural Study of Aluminum Nitride Thin Films: Epitaxy on the Two Orientations of Sapphire and Texturing on Si

1995 ◽  
Vol 395 ◽  
Author(s):  
K. DOVIDENKO ◽  
S. OKTYABRSKY ◽  
J. NARAYAN ◽  
M. RAZEGHI
Keyword(s):  
Thin Films ◽  
Wide Band ◽  
High Resolution Electron Microscopy ◽  
Epitaxial Relationship ◽  
Wide Band Gap ◽  
Cross Sectional ◽  
Plan View ◽  
Microstructural Study ◽  
Resolution Electron ◽  
Relationship Of

ABSTRACTThe microstructural study of wide-band gap semiconductor AlN thin films grown on (0001) and (1012) sapphire and (111), (100) Si was carried out using plan-view and cross-sectional high-resolution electron microscopy and x-ray diffraction. The films were grown by MOCVD from TMAl + NH3 + N2 gas mixture. Epitaxial relationship for AIN grown on (0001)α 01-Al2O3 was determined to be the following: (0001)AIN ║ (0001)sap with the 30° in-plane rotation - [0110]AIN ║ [1210]sap. We report also TEM observation of the following epitaxial relationship of the AlN/(1012)α-Al2O3 heterostructure: (1120)AIN ║ (1012)sap; [0001]AIN ║ [1011]sap and [1100] AIN ║ [1210]sap. These epitaxial relationships were determined to be controlled by the bonding of Al and O ions at the interface. The study of interfaces and the defects present in the film was also carried out. Main type of defects were established to be inverted domain boundaries, misfit and threading dislocations - in the films on (0001) sapphire, and stacking faults of high density in the films on (1012) sapphire. The epitaxial AIN films on (0001) sapphire contained dislocation density about 1010 cm−2 and exhibited device quality electrical characteristics. The films on both orientations of Si were found to be highly <0001> textured polycrystalline.

Study of the growth mechanism of highly in-plane aligned α-axis YBa2Cu3O7−x thin films on LaSrGaO4 substrate by high resolution electron microscopy

1996 ◽  
Vol 11 (12) ◽  
pp. 2951-2954 ◽  
Author(s):  
J. G. Wen ◽  
S. Mahajan ◽  
H. Ohtsuka ◽  
T. Morishita ◽  
N. Koshizuka
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Cross Sectional ◽  
Plan View ◽  
Oriented Film ◽  
Resolution Electron ◽  
Average Size

Highly in-plane aligned α-axis YBa2Cu3O7−x thin films deposited on (100) LaSrGaO4 substrates by a self-template method were studied by high-resolution electron microscopy along three orthogonal 〈100〉 axes of the substrate. Plan-view images confirm that the majority of the film preferentially aligns across the entire substrate except for very few misaligned domains with average size 10 nm2. Cross-sectional images along the [100] orientation of YBa2Cu3O7−x reveal that in-plane aligned α-axis YBa2Cu3O7−x is grown on a template layer dominated by c-axis oriented film. This strongly suggests that the in-plane alignment of α-axis YBa2Cu3O7−x thin films on (100) LaSrGaO4 substrates is governed by the different stresses along the b and c axes of the substrate. Cross-sectional images along [001] of the YBa2Cu3O7—x thin film reveal that the 90° domains easily nucleate in the region between α-axis YBa2Cu3O7—x and the YBa4Cu3Ox phase. Cracks along the (001) plane of YBa2Cu3O7−x are found to be due to the large mismatch between the c parameters of the thin film and substrate.

A HREM study of V/Al2O3 interface

1992 ◽  
Vol 50 (1) ◽  
pp. 146-147
Author(s):  
Y. Ikuhara ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Cross Sectional ◽  
Plan View ◽  
Resolution Electron

The interface structure between vanadium and the R-plane of sapphire (α-Al2O3) was studied by conventional and cross-sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface.A 57 nm thick vanadium film was deposited on the (1102) (R) plane of sapphire by molecular beam epitaxy (MBE) at a substrate temperature of 920 K in a vacuum of 10-10torr. The HREM observations of the interface were done from three directions: two cross-sectional views (parallel to [0221]Al2O3 and [1120]Al2O3) and a plan view (parallel to [2201]Al2O3) by a top-entry JEOL 4000EX electron microscope (400 kV).

Morphology of Vapor Evaporated Mo Thin Films

1991 ◽  
Vol 222 ◽  
Author(s):  
Y. Cheng ◽  
M. B. Stearns
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
Large Angle ◽  
High Resolution Electron Microscopy ◽  
Cross Sectional ◽  
X Ray ◽  
X Ray Scattering ◽  
Resolution Electron ◽  
Deposition Angle

ABSTRACTStudies were made of the dependence of the morphology of Mo films, prepared by ebeam evaporation in an UHV system, on the substrate temperature and deposition angle. The main characterization techniques used were large angle x-ray scattering and cross-sectional high resolution electron microscopy.

scholarly journals High-temperature structural behavior of Ni/Au Contact on GaN(0001)

2001 ◽  
Vol 6 ◽  
Author(s):  
Chong Cook Kim ◽  
Jong Kyu Kim ◽  
Jong-Lam Lee ◽  
Jung Ho Je ◽  
Min-Su Yi ◽  
...  
Keyword(s):  
Structural Evolution ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
X Ray Scattering ◽  
Smooth Interface ◽  
Resolution Electron ◽  
Device Reliability ◽  
Relationship Of

We investigated the structural evolution of the Ni/Au contact on GaN(000l) during annealing in N2, using in-situ x-ray diffraction, anomalous x-ray scattering, and high resolution electron microscopy. GaN decomposition occurred mostly along GaN dislocations at temperature higher than 500°C. The decomposed Ga diffused into Au and Ni substitutional positions, and the decomposed nitrogen reacted with Ni, forming Ni4N. Interestingly, Ni4N was grown epitaxially. The epitaxial relationship of the Ni4N, Au, and Ni was identified as M(111)//GaN(0002) and M[1 −1 0]//GaN[1 1 −2 0] (M= Ni4N, Au, and Ni). At dislocation free regions, however, the atomically smooth interface remained intact up to 700 °C. Remarkable improvement of device reliability is expected in the contact on dislocation free regions compared with the contact on dislocations.

High Resolution Electron Microscopy (HREM) Study of Chemically Vapor Deposited Polycrystalline Si1-xGex Thin Films

2000 ◽  
Vol 609 ◽  
Author(s):  
W. Qin ◽  
D. G. Ast ◽  
T. I. Kamins
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
Repeat Unit ◽  
High Resolution Electron Microscopy ◽  
Second Order ◽  
Plan View ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Polysilicon Films

ABSTRACTThe microstructure of polysilicon and Si0.69Ge0.31 thin films, grown by chemical-vapordeposition (CVD) on oxidized silicon wafers covered with a very thin polysilicon seed layer, was investigated using high-resolution electron microscopy (HREM). The plan-view HREM images showed that polysilicon films contained less substructure inside grains and had fewer multiple twins and more extended twin bands than Si0.69Ge0.31. On the other hand, only SiGe contained multiple twins with five-fold symmetry. The atomic model of the second-order symmetric twin boundary proposed for Si and based on the insertion of five-member and seven-membered rings was found to describe the atomic structures of second-order symmetric twin boundaries in Si0.69Ge0.31 as well. Within the accuracy of HREM, the repeat unit of the boundary was the same in Si0.69Ge0.31 and Si.

Microstructural dependence of magnetic properties of Pt/Co multilayers for magneto-optical recording devices

1991 ◽  
Vol 49 ◽  
pp. 778-779
Author(s):  
Z.G. Li ◽  
P.F. Carcia
Keyword(s):  
Magnetic Properties ◽  
High Resolution Electron Microscopy ◽  
Optical Recording ◽  
Total Thickness ◽  
Cross Sectional ◽  
Sputtered Films ◽  
Resolution Electron ◽  
Relationship Of ◽  
The Relationship ◽  
Microstructure And Magnetic Properties

Pt/Co ultrathin multilayer films are a new candidate for magneto-optical (MO) recording devices. We have previously shown that their magnetic properties are improved by sputtering them with either Kr or Xe instead of Ar. Specifically, Arsputtered films have too small coercivity for recording. In this study we demonstrate that high resolution electron microscopy (HREM) is a powerful technique to study the relationship of the multilayer microstructure and magnetic properties. We used a Philips CM30 and a JEM 2000FX microscope to study multilayers with a typical total thickness in the 10 nm range, consisting of only 1-2 atomic layers of Co and 4-6 atomic layers of Pt.Figure 1 compares the cross sectional microstructure of nearly identical Pt/Co multilayers (~10x[4Å Co+13Å Pt]) sputtered in (A) 7 mTorr of Ar, (B) 7 mTorr of Kr, and (C) 5 mTorr of Xe. The layers sputtered in Ar are extremely flat and continuous. Sputtering with a larger mass gas (Kr or Xe) progressively increased the layer roughness, and the lateral continuity of layers was more frequently interrupted by grain boundaries, which were very distinct in Kr- and Xe-sputtered films compared to Ar-sputtered films.

Cross-sectional time-resolved high-resolution electron microscopy of epitaxial growth of Au on MgO

1996 ◽  
Vol 54 ◽  
pp. 982-983
Author(s):  
T. Kizuka ◽  
N. Tanaka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Epitaxial Growth ◽  
High Resolution Electron Microscopy ◽  
Vacuum Deposition ◽  
Cross Sectional ◽  
Time Resolved ◽  
Plan View ◽  
Resolution Electron

Vapor phase epitaxial growth techniques are indispensable for production of thin film electric devices. Various structural analyses have been attempted to evaluate the epitaxial growth. Conventional transmission electron microscopy (CTEM) is a most useful method. In particular, it is known that a plan-view time-resolved CTEM of in-situ vacuum-deposition in a microscope can analyze each process of epitaxial growth. The nucleation in vacuum-deposition was also in-situ observed by a time-resolved high resolution electron microscopy (TRHREM). However many unresolved problems still remain in the studies of the epitaxial growth because it is difficult to observe the epitaxial interfaces less than a few nanometer under appropriate conditions. Much more advanced techniques are required for electron microscopy to obtain detailed information.In the present study, a TRHREM for the cross-sectional observation was developed to elucidate the epitaxial growth process in vacuum-deposition.Gold (Au) was vacuum-deposited on (001) surfaces of the magnesium oxide (MgO) substrates at room temperature in a specimen chamber of a 200-kV high-resolution electron microscope (JEOL, JEM2010).

Interface Characterization of AlN/TiN/MgO(001) Prepared by Molecular Beam Epitaxy

1999 ◽  
Vol 14 (4) ◽  
pp. 1597-1603 ◽  
Author(s):  
X. L. Ma ◽  
N. Shibata ◽  
Y. Ikuhara
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Theoretical Calculations ◽  
Substrate Surface ◽  
High Resolution Electron Microscopy ◽  
Structure Type ◽  
Geometrical Model ◽  
Cross Sectional ◽  
Resolution Electron ◽  
Relationship Of

The AlN/TiN/MgO(001) interfaces, prepared by molecular beam epitaxy, have been characterized by cross-sectional high-resolution electron microscopy (HREM). The thin TiN buffer layer, with the thickness of 40 nm, is epitaxially grown on the MgO(001) substrate. Owing to the same structure-type as well as the small mismatch of their lattice parameters, the growth is governed by the parallel orientation relationship of (001)TiN||(001)MgO, (010)TiN||(010)MgO, and (111)TiN||(111)MgO. Two kinds of processes of the hexagonal AlN epitaxial growth on the as-received TiN(001), differed by the (0001)AlN plane parallel to, and the (1012) plane approximately parallel to the MgO substrate surface, respectively, are identified, and within them, several cases are classified which are based on the consideration of crystallographic symmetry. Theoretical calculations based on the geometrical model that was recently proposed and applied to a number of epitaxial systems have been carried out to rationalize these observations.

Structural Evolution of Ni/Au Contact on GaN(0001)

2000 ◽  
Vol 639 ◽  
Author(s):  
Chong Cook Kim ◽  
Jong Kyu Kim ◽  
Jong-Lam Lee ◽  
Min-Su Yi ◽  
Jin-Woo Kim ◽  
...  
Keyword(s):  
Structural Evolution ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Thermally Activated ◽  
X Ray Scattering ◽  
Resolution Electron ◽  
Relationship Of

ABSTRACTWe investigated the structural behavior of the Ni/Au contact on GaN(000l) during annealing in N2, using in-situ x-ray diffraction, anomalous x-ray scattering, and high resolution electron microscopy. Thermally activated atomic mobility caused the two metal atoms, Au and Ni, to interdiffuse during annealing and form solid solutions. At temperature higher than 500°C, GaN decomposition and reactions occurred mostly along GaN dislocations. By decomposed nitrogen reacted with Ni, interestingly, epitaxial Ni4N phase was formed. The epitaxial relationship of the Ni4N, Au, and Ni was identified as M(111)//GaN(0002) and M[0 1 1]//GaN[0211] (M= Ni4N, Au, and Ni).

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

Sign in / Sign up

Export Citation Format

Share Document