Planar Transmission Electron Microscopy Research Articles

The Effect of Carbon Contamination and Stress on Dislocation Generation in SIMOX

SIMOX films with dislocation densities below the detection limit of planar transmission electron microscopy (106/cm2) have been achieved using a single ion implant of . The realization of these low defect density films at the relatively high implant dose level is associated with low carbon content in the SIMOX layer . Thus, it can be concluded that control of the carbon in SIMOX films may obviate the need for multiple implants to achieve low defect densities. It is also observed that stress in the as‐implanted SIMOX films, as measured by Raman line shift, is a good index of the dislocation formation during subsequent annealing of the SIMOX film.

Orientation dependence of twinning characteristics in Y-Ba-Cu-O superconducting thin films

The twinning characteristics of epitaxial and textured superconducting thin films grown on (100) SrTiO3 and (100) MgO substrates have been found to be dependent on the film orientation. Microstructural details of thin films deposited by the pulsed-laser evaporation technique followed by annealing in oxygen and helium atmospheres at 900 °C for short time intervals were examined using cross-section and planar transmission electron microscopy. The number density of twins in textured thin films having their c axis normal to the substrate were found to be significantly higher than those in textured films having their c axis parallel to the substrate. Calculations of stresses induced in thin films as a result of the tetragonal to orthorhombic phase transition indicated that large shear stresses and strain energies were introduced in films with their c axis perpendicular to the substrate, thereby resulting in a high number density of twins in this orientation.

The role of implantation temperature and dose in the control of the microstructure of SIMOX structures

Abstract Single-crystal ⇇100↩ silicon wafers have been implanted with 200 keV oxygen ions over a dose range of 0.1×1018 O+ cm-2 to 1.4×1018 O+ cm-2 and a temperature range of ≈250°C to 550°C. The specimens have been analyzed, both before and after high-temperature annealing, using a variety of techniques, such as cross-sectional and planar Transmission Electron Microscopy (TEM), Rutherford backscattering (RBS), and ion channelling, Secondary Ion Mass Spectroscopy (SIMS), Infra-red Spectroscopy (IR), and Raman Spectroscopy. This has enabled us to evaluate the development of the SIMOX structure both with respect to implantation temperature and dose and also with respect to annealing temperature and time.

Transmission electron microscopy studies of brown and golden titanium nitride thin films as diffusion barriers in very large scale integrated circuits

The usefulness of reactively sputtered TiN as a diffusion barrier in the AlTiN/Ti/Si metallization scheme in very large scale integration was reported in a previous publication. Two types of TiN thin films were studied in these experiments. Depending on the applied substrate bias voltage, the resulting TiN films can have different properties. Under no-bias conditions, dark brown colored films (called B films) with low density (3.22 g/cm3), high electrical resistivity (∼400 μΩ cm), and 5%–8% O2 are obtained. A+ -75 V dc substrate bias, bright golden colored films (called G films) with high density (∼5.0 g/cm3), low resistivity (∼20 μΩ cm), and negligible O2 are obtained. Even though the B films contain more O2, the G films were found to be better diffusion barriers for silicon. To investigate the effect of film microstructure on the diffusion barriers, cross-sectional and planar transmission electron microscopy samples were used. Both, brown and golden, types of films have columnar grain structure with approximately the same size (∼400–500 Å), contrary to fine-grained structure observed for G films by some other groups. The columns in the G films increase in size with an increase in distance from the TiN/Si interface, while the grain size remains almost constant in the B films. The intergrain structure also differs considerably; the grains in G films are very closely packed while they are very loosely bound in the B films. The intergrain voids in the B films can act as an easy path for silicon diffusion. Also, these films were studied by Rutherford backscattering spectroscopy, Auger electron spectroscopy, and x-ray diffraction to understand the diffusion mechanisms.

Correlation of Postetch Residues to Deposition Temperature in Plasma Etched Aluminum Alloys

A study of the dependence of postetch residues on deposition temperature was carried out on Al(1%Si), Al(2%Cu), Al(4%Cu), and . The postetch residues were analyzed using Auger electron spectroscopy, and correlated to the film structure which was characterized using Auger depth profiling, and cross‐sectional and planar transmission electron microscopy. The residues seen for the Al(1%Si) and Al(Cu) alloys could be explained on the basis of the size and distribution of a secondary phase involving the alloying element. The results for the also indicated a dependence on film structure. In general, residue free etching could be obtained for alloys deposited at temperatures below 200°C.

Three Dimensional Characterization of Interfaces in Semiconductors by Scanning Electron Microscopy

AbstractIn many semiconductor materials problems, structural characterizations must be achieved in both the lateral and vertical dimensions. Although a combination of cross-sectional and planar transmission electron microscopy can provide this information, the sample preparation time is demanding and only relatively small volumes of material are examined. We describe here an alternative approach in which the charge collection (‘CCM’) imaging mode of the scanning electron microscope (SEM) is used. It is shown that, by varying the incident electron beam energy, electricallly active defects at different positions beneath the entrance surface of the material can be imaged and their depth estimated.

Transmission electron microscopy of liquid phase epitaxial Hg1−xCdxTe layers on CdTe substrates

Epitaxial Hg1−xCdxTe films were grown on (111)A CdTe substrates by the tellurium solvent, horizontal tube slider liquid phase epitaxy technique. Their microstructures were subsequently investigated by both planar and cross-sectional transmission electron microscopy (TEM). Planar TEM showed the top surface of the films to be precipitate free with a general dislocation density <106/cm2 except for localized regions containing high dislocation densities associated with linear surface features on the Hg1−xCdxTe. Cross-sectional TEM showed the interface region to be nonplanar due to meltback during epilayer growth. A three-dimensional dislocation structure was confined to a band in the interface region having a graded Hg composition.

Defect Characterization in Monocrystalline Silicon Grown Over SiO2

Crystallographic defect structures in monocrystalline silicon films grown over layers have been characterized by cross‐section and planar transmission electron microscopy. Overgrowths of epitaxial silicon films on layers have been seeded from single crystal substrates through openings in the layers. Defect structures have been studied as a function of substrate orientation, seeding procedure, and growth temperature. Defect densities have been dramatically reduced through first‐order optimization of the above parameters.