Papers by Keyword: Epitaxy

Abstract: 70-um thick homoepitaxial layers with very low defect density were grown on 6-inch 4° off-axis wafers using hot-wall chemical vapor deposition (CVD). Process optimization resulted in reduction of the density of triangular defects from 1.01 cm^-2 to 0.14 cm^-2. The treatment of wafer (CMP or selection) was essential. The in-situ etch process was optimized prior to the epitaxial growth. Junction Barrier Schottky diodes fabricated on the epitaxial films presented a typical I–V characteristic and a block voltage of 6500 V.

Abstract: The knowledge of elastic fields caused by dislocation networks is a network that is sometimes indispensable for the interpretation of images obtained by electron microscopy and for the understanding of physical phenomena. In this axis, the present work makes it possible to determine the elastic behavior of a thin bimetallic isotropic elasticity in the case where the hetero-interface is covered with a parallel network of wedge type detuning dislocations. The topology of the free surfaces is calculated according to the total thickness of the bimetallic strip until a relaxation is reached for a thickness "h" called critical thickness.

Abstract: Quantum technology is a field of significant interest that will benefit many applications including communications and sensing. SiC is a promising material for quantum applications such as quantum memories, due to point defects, specifically V_Si, in the material, which result in long spin coherence times. We have found that no V_Si are present in our epitaxially grown unintentionally and nitrogen-doped 4H-SiC with electron concentrations ranging from 10¹⁴ to 10¹⁸ cm^-3. We create these vacancies using electron irradiation, in concentrations from single defects to ensembles. To utilize the defect luminescence for realistic applications, we have fabricated the SiC into photonic crystal arrays. We present the processing steps required to create photonic crystal cavities in SiC and subsequent challenges.

Abstract: The development of bipolar 4H-SiC devices for high blocking voltages requires the growth of high carrier lifetime epitaxial layers with low Z_1/2 concentrations. This paper shows a comprehensive investigation of the influence of epitaxial growth parameters (C/Si ratio and growth temperature) on Z_1/2 concentration and minority carrier lifetime. On the basis of a discovered exponential correlation of Z_1/2 with the C/Si ratio and growth temperature, a competitive low Z_1/2 concentration of 1.9∙10¹² cm^-3 could be achieved by lowering the growth temperature and switching to higher C/Si ratio. Thermodynamic considerations by an Arrhenius approach reveal a dependency of the formation enthalpy of Z_1/2 on the thermal process and process conditions of the epitaxial growth. Furthermore, the correlation between Z_1/2 and the effective minority carrier lifetime confirms the occurrence of a necessary second recombination mechanism beside the common recombination at deep levels by Shockley-Read-Hall for low Z_1/2 concentration.

Abstract: Hot filament CVD (HFCVD) growth of undoped 4H-SiC epitaxial layers on 100 mm n-type 4^o-off 4H-SiC substrates is presented as an alternate growth method for the first time. High quality crystalline material with a low density of polytype inclusions has been demonstrated and characterized with optical micrographs, SEM imaging, micro-Raman measurements, and high resolution XRD. Typical growth rates are ~3 μm/hour. Double rocking omega scans revealed diffraction peaks with a FWHM of 23 arcsec.

Abstract: First objective of present contribution is to supply a compact description of two thickness-dependent characteristics of state of the art as-grown 3C-SiC/Si templates: structural quality and surface morphology. Second objective is to point out the benefits of surface planarization and indicate the temperature limits of thermal treatment that can be applied to polished 3C-SiC/Si templates without deterioration of planarization results. We believe that this kind of overview, based on our long term experience in fabrication of 3C-SiC/Si templates, may be useful for the scientific community working on future applications of cubic silicon carbide polytype.

Abstract: High quality SiC Epilayers are essential for the development of high performance power devices. Killer defects such as triangular defects could cause leakage current paths within the high voltage SiC devices. This paper reports on the recent advances in 4H-SiC epitaxial growth toward high-throughput production in a commercial planetary reactor. The triangular defects are suppressed by the optimized pre-etching process, and the physics behind was investigated. The doping and thickness uniformities of the intra-wafer and wafer-to-wafer have also been improved.

Abstract: Complex analysis of the quality of the surface of the multicomponent epitaxial layers A^IIIB^V compounds grown at the different conditions of temperature gradient zone recrystallization was performed. Main parameters that determine the quality of the surface and structural perfection of multicomponent heterostructures AlInGaPAs / GaAs have been found: the temperature gradient, the composition of the solution-melt, subcooling, matching the lattice parameters and the CTE of the layer and the substrate, the substrate orientation.

Abstract: We report on the growth of bulk 3C-SiC by sublimation on epitaxial seeding layers (3C-SiC/Si) from chemical vapor deposition. We have reached a materials thickness of 0.85 mm and an area of 10.5 cm² which can be enlarged further. The high crystalline quality is characterized by the absence of secondary polytype inclusions and the absence double position grain boundaries.

Abstract: “HF Last” process are widely used as pre epi cleans. They enable a Si-H surface to grow a perfect Si layer by epitaxy. Nonetheless, such hydrophobic wafers are extremely sensitive to watermarks formation during the wafer drying. A design of experiments has been used to determine which parameters impact their formation on a single wafer cleaning tool. Plus, the silicon surface stability has been compared between this tool and an immersion batch cleaning tool.