Papers by Keyword: Silicon-Germanium (SiGe)

Abstract: The IR absorption spectra and kinetics of the oxygen solid solution decay were studied in the Si1¡xGex crystals (0 · x · 0:055) plastically deformed at 680±C up to the 2{5% residual strain. It is found that the defects of non-dislocation nature, the dislocation trails, are formed during the plastic deformation of all studied SiGe crystals. The ¯ne structure of the IR absorption spectra around the 1000 cm¡1 wave number is found to be nearly identical in the pure Si (no Ge) samples and Si1¡xGex crystals with x · 0:02. At higher x the ¯ne structure was not detected due to the alloy-related broadening. In all studied crystals, the decay of the supersaturated oxygen solid solution at 650±C is determined by oxygen agglomeration at the dislocation trails as shown by the comparison with the samples annealed at 1150±C.

Abstract: The measurements of stress induced dichroism on oxygen absorption band near 1107 cm-1 in Si1-xGex compounds and subsequent kinetics of the dichroism recovery upon isothermal annealing have been carried out. It has been found that the magnitude of introduced by uniaxial stress dichroism decreases with increasing Ge content. Two components in the dichroism annealing kinetics have been found. On the basis of studying absorption spectra of samples under investigations it was assumed that two components in relaxation correspond to the diffusion of oxygen being in a different nearest environment: the one component corresponds to oxygen surrounded by silicon atoms and the second one to the oxygen the neighbour of which is Ge atom. Diffusivity for each of the components has been determined. It has been shown that the diffusivity of oxygen that is in both of these configurations decreases with increasing Ge content.

Abstract: NiPt self-aligned silicide (salicide) has become a major candidate for the 45nm node due to its better thermal stability and the surface morphology of NiSi on Si substrate [1,2]. SiGe has been proposed for PMOS strain engineering [3]. The relevant SiGe oxidation behavior [4], reaction with platinum [5] and thermal stress behavior [6] are important factors in developing a process for 45nm NiPt salicide over SiGe stressor. These concerns require the review of the current process for NiPt to verify its compatibility and extendibility.

Abstract: Several device concepts have been further evaluated after the successful implementation of epitaxial Si, SiGe and/or Si:C layers. Most of the next device generations will put limitations on the thermal budget of the deposition processes without making concessions on the epitaxial layer quality. In this work we address the impact of ex-situ wet chemical cleans and in-situ pre-epi bake steps, which are required to obtain oxide free Si surfaces for epitaxial growth. The combination of defect measurements, Secondary Ion Mass Spectroscopy, photoluminescence, lifetime measurements, and electrical diode characterization gives a very complete overview of the performance of low-temperature pre-epi cleaning methods. Contamination at the epi/substrate interface cannot be avoided if the pre-epi bake temperature is too low. This interface contamination is traceable by the photoluminescence and lifetime measurements. It may affect device characteristics by enhanced leakage currents and eventually by yield issues due to SiGe layer relaxation or other defect generation. A comparison of state of the art 200 mm and 300 mm process equipment indicates that for the same thermal budgets the lowest contamination levels are obtained for the 300 mm equipments.

Abstract: Strained silicon engineering was first used at the 90-nm node. Nowadays, a series of techniques has seen wide-spread use and many derivatives are available because of their ease of integration and cost-effective features [ , ]. As a main part of stressor technique, embedded SiGe-S/D technology is reported to improve the pMOSFET drive current [ , ].

Abstract: Single crystal Si, Si0.948Ge0.052 and Si0.66Ge0.34 diodes as well as Ge transistor structures with high electroluminescence (EL) intensities in the region of interband transitions at room temperature were fabricated by different techniques and their luminescence properties were studied. By varying the Ge content in the solid solution, one can control the wavelength at the emission maximum in the range of 1.1 - 1.8 μm. The integrated EL intensity varies by a factor of less than two in the temperature ranges of 80 - 500 and 80 - 300 K for Si and SiGe LEDs, respectively. Si LEDs can effectively operate, at least, up to ~200°C. The data analysis shows that recombination involving excitons is the dominant mechanism of near-band-edge radiative recombination in all the light-emitting structures at room temperature. Some of the structures have record values of EL intensity and/or quantum efficiency, so they can be used as effective light emitters in Si optoelectronics. In particular, Si LEDs were designed with a small p-n junction area of 8x10-3 mm2 and a radiation power of 0.3 mW. The record total emission power of 46 mW was achieved in solar cell LEDs with an emitting surface area of 3 сm2. The internal quantum efficiencies of 0.5% and 0.3% were recorded in Si0.948Ge0.052 and Si0.66Ge0.34 LEDs at the wavelengths of 1.15 and 1.3 μm, respectively. Room temperature near-band-edge EL was first observed in Ge structures.

Abstract: The recent progress of advanced millisecond annealing (MSA) technology is discussed for the application to the advanced logic LSI fabrication processes. The combination with conventional spike annealing and MSA is proving practical to reduce the parasitic resistance and control the dopant diffusion. The characterization result of advanced 45 nm generation devices including the channel straining technology using embedded SiGe epitaxial growth is described with the arrangements of process flow and annealing steps. MSA has a principle problem of the annealing temperature variation depending on the optical properties of materials on the wafer surface because the annealing process time is similar to the heat transfer time. In the device scale, the variation of temperature is examined as the exact temperature with newly proposed evaluating methods used for the first time in this industry.