Papers by Keyword: Ge

Abstract: In this atomic-scale study on technologically relevant group IV semiconductors, Ge and SiGe, we relate surface chemistry, in particular the nature of surface oxides, to wet etching kinetics. ICP-MS quantification of Ge in HCl solution containing H₂O_­2 as the oxidizing agent showed that the Si bulk concentration strongly impacted the etching kinetics. Post operando synchrotron XPS provided insight into the surface oxide chemistry involved in the etching process: a non-homogeneous porous layer with a depletion of Ge components at the outer surface due to pull out effects.

Abstract: New approaches to enhance properties of silicon based quantum dot heterostructures for optical device application were developed. That is strain driven heteroepitaxy, small-sized quantum dots, elemental compositions of the heterointerface, virtual substrate, plasmonic effects, and the quantum dot charging occupation with holes in epitaxially grown Ge quantum dots (QDs) on Si (100). Experiments have shown extraordinary optical properties of Ge/Si QDs heterostructures and mid-infrared quantum dot photodetectors performance.

Abstract: The incorporation of Germanium (Ge) in 4H-SiC has recently being reported as enabling an increase of the electron mobility in n-type doped layers. The present work aims at evaluating the impact of the Ge doping on two types of SiC devices: Merged PiN-Schottky (MPS) diodes and Trench MOSFETs.

Abstract: of these new materials have necessitated the evaluation of new chemicals and processing methods. The control of the Dissolved Oxygen (DO) concentration to suppress Cu corrosion is well established in BEOL processing and likewise in order to achieve a hydrophobic surface after pre-epi cleaning in FEOL surface preparation [2].

Abstract: We report characteristics of quantum dot (QD) sensitized solar cells using Si nanoparticles and Ge nanoparticles. Si nanoparticles were synthesized by multi-hollow discharge plasma chemical vapor deposition, whereas Ge nanoparticles were done by a radio frequency magnetron sputtering using Ar+H₂ under high pressure conditions. The electrical power generation from Si QDs and Ge QDs was confirmed. Si QD sensitized solar cells show an efficiency of 0.024%, fill factor of 0.32, short-circuit current of 0.75 mA/cm² and open-circuit voltage of 0.10 V, while Ge QD sensitized solar cells show an efficiency of 0.036%, fill factor of 0.38, short-circuit current of 0.64 mA/cm² and open-circuit voltage of 0.15 V.

Abstract: We investigated impacts of the Ar and CF₄plasma during reactive ion etching (RIE) on defect formation in the Ge substrates using the deep-level-transient-spectroscopy (DLTS) technique. It was found that the Ar plasma causes the roughening of the Ge surface. Moreover, the Ar plasma induces a defect with an energy level of 0.31 eV from the conduction band minimum in the Ge substrate, confirming by DLTS spectra. On the other hand, the CF₄ plasma hardly induces the surface roughness of Ge. However, the CF₄ plasma induces many kinds of electron and hole traps. It should be noted that the defects associated with Sb and interstitials are widely distributed to around 3-µm.

Abstract: To develop a new low-temperature crystallization technique, annealing characteristics of a-GeSn/Si (100) structures are investigated. It is revealed that epitaxial growth accompanying Si-Ge mixing is generated at temperatures in the liquid-solid coexisting region of the Ge-Sn system. The annealing temperature necessary for epitaxial growth is significantly decreased by increasing annealing time and/or Sn concentration. Consequently, epitaxial growth at 300°C becomes possible. These findings are expected to be useful to realize next-generation large-scale integrated circuits, where various multi-functional devices are integrated.

Abstract: Thermal oxidation of Ge was performed in dry oxygen ambience at atmospheric pressure at temperature ranging between 375 and 575°C. From SE analysis, the slope of Ge oxide growth and extinction coefficient (k) increases while refractive index (n) does not change with oxidation temperature. The reduction of activation energy for Ge thermal oxidation was explained by the retardation of diffusion oxidant through GeO₂ film during Ge oxidation. The generation of an oxygen-defect region in the Ge oxide layer at 490°C oxidation was confirmed by XPS analysis and an O₂ anneal at 375°C was effective to reduce this oxygen deficiency.

Abstract: GeO₂ has been doped solely and together with SiO₂ into barium titanate ceramics by mixing and calcination. The microstructure and dielectric properties of doped BaTiO₃ have been characterized. When doped in BaTiO₃, Ge⁴⁺ ion could incorporated into the crystal lattice of BaTiO₃ to occupied Ti⁴⁺ sites. For relative smaller Ge⁴⁺ ion, the tetragonal phase could be enhanced. As dielectric properties have strong relation to tetragonal phase. The relative permittivity could be increased in this mechanism. However, the high leakage current which induced by more ionic defect was also lead to high dielectric loss. Besides, the assemble in grain boundary by Ge⁴⁺ ion may also have effect. Results on the GeO₂-SiO₂ co-doped sample showed that the mechanisms of Ge doping and Si doing could happen at one time.

Abstract: Cleaning photoresist from semiconductor wafers during the transistor formation in the front end of the line (FEOL) becomes more challenging with ever smaller nodes. First of all the resists do become more difficult to clean with decreasing node size, because implantation energy increase and the resist becomes more complex (to comply with the reduced wave length of the laser light for the lithography) at future node sizes. This results in more cross linked / polymerized photoresist, which is harder to (wet) strip. Additionally, the requirements on material compatibility of the cleaning solution increase, as more elements are used to build the transistor less than a monolayer of these materials can be removed during a single cleaning step.