Browsing by Subject "Silicon alloys"

Now showing 1 - 4 of 4

Open Access
Defect reduction of Ge on Si by selective epitaxy and hydrogen annealing
(2008-10) Yu, H.-Y.; Park, J.-H.; Okyay, Ali Kemal; Saraswat, K. C.
We demonstrate a promising approach for the monolithic integration of Ge-based nanoelectronics and nanophotonics with S-ilicon: the selective deposition of Ge on Si by Multiple Hydrogen Annealing for Heteroepitaxy (MHAH). Very high quality Ge layers can be selectively integrated on Si CMOS platform with this technique. We confirm the reduction of dislocation density in Ge layers using AFM surface morphology study. In addition, in situ doping of Ge layers is achieved and MOS capacitor structures are studied. ©The Electrochemical Society.
Open Access
Germanium for high performance MOSFETs and optical interconnects
(2008-10) Saraswat, K. C.; Kim, D.; Krishnamohan, T.; Kuzum, D.; Okyay, Ali Kemal; Pethe, A.; Yu H.-Y.
It is believed that to continue the scaling of silicon CMOS innovative device structures and new materials have to be created in order to continue the historic progress in information processing and transmission. Recently germanium has emerged as a viable candidate to augment Si for CMOS and optoelectronic applications. In this work we will first review recent results on growth of thin and thick films of Ge on Si, technology for appropriate cleaning of Ge, surface passivation using high-κ dielectrics, and metal induced crystallization of amorphous Ge and dopant activation. Next we will review application of Ge for high performance MOSFETs. Innovative Si/Ge MOS heterostructures will be described with high on current and low off currents. Finally we will describe optical detectors and modulators for on-chip and off-chip interconnect. Successful integration of Ge on Si should allow continued scaling of silicon CMOS to below 22 nm node. ©The Electrochemical Society.
Open Access
Initial stages of SiGe epitaxy on Si(001) studied by scanning tunneling microscopy
(Elsevier BV, 1995) Oral, A.; Ellialtioglu, R.
We have studied the initial stages of strained SiGe alloy growth on the Si(001)-(2 × 1) surface by scanning tunneling microscopy. The Si0.36Ge0.64 alloy was grown on the silicon substrate at various coverages (0.13-3.6 ML) and at different temperatures (∼ 310-470°C). The growth was one dimensional, preferring the direction perpendicular to the underlying silicon dimer rows at low coverages and low temperatures. Anti-phase boundaries were observed to lead multi-layer growth. Strong interaction between the overlayer and the substrate was found to buckle the substrate as well as SiGe dimers. Different growth mechanisms, island formation and step flow, were identified at low and high substrate temperatures. (2 × n) ordering of the strained overlayer was only observed at an intermediate growth temperature (∼ 390°C). © 1995.
Open Access
Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys
(Elsevier, 2013) Amini, R.; Shamsipoor, A.; Ghaffari, M.; Alizadeh, M.; Okyay, Ali Kemal
Mechano-synthesis of Fe-32Mn-6Si alloy by mechanical alloying of the elemental powder mixtures was evaluated by running the ball milling process under an inert argon gas atmosphere. In order to characterize the as-milled powders, powder sampling was performed at predetermined intervals from 0.5 to 192 h. X-ray florescence analyzer, X-ray diffraction, scanning electron microscope, and high resolution transmission electron microscope were utilized to investigate the chemical composition, structural evolution, morphological changes, and microstructure of the as-milled powders, respectively. According to the results, the nanocrystalline Fe-Mn-Si alloys were completely synthesized after 48 h of milling. Moreover, the formation of a considerable amount of amorphous phase during the milling process was indicated by quantitative X-ray diffraction analysis as well as high resolution transmission electron microscopy image and its selected area diffraction pattern. It was found that the α-to-γ and subsequently the amorphous-to-crystalline (especially martensite) phase transformation occurred by milling development.