Behavior of high dose O+-implanted Si/Ge/Si structures

The synthesis of a buried oxide layer in multilayer Si/Ge/Si structures by the implantation of high doses of 200 keV O+ ions is studied by Rutherford backscattering analysis. The presence of Ge is found to have a minimal effect upon the mass transport of excess oxygen and interstitial silicon. Infrared transmission spectroscopy and x-ray photoelectron spectroscopy confirm that the oxygen atoms bond preferentially to silicon forming silicon dioxide and SiOx, where x<2, with no evidence for Ge—O bonding

Self-determined citizens? New forms of civic activism and citizenship in Armenia

This article examines the recent emergence and growth of grassroots social movements in Armenia which are locally known as ‘civic initiatives’. It considers what their emergence tells us about the development of civil society and the changing understandings and practices of citizenship in Armenia in the post-Soviet period. It analyses why civic initiatives explicitly reject and distance themselves from formal, professionalised NGOs and what new models of civic activism and citizenship they have introduced. It argues that civic initiatives embrace a more political understanding of civil society than that which was introduced by Western donors in the 1990s

Comparison of arsenic diffusion in Si_1-xGe_x formed by epitaxy and Ge+ implantation

A comparison is made of arsenic diffusion in Si0.95Ge0.05 produced by epitaxy and ion beam synthesis using a 2 x 1016 cm-2 Ge+ implant into silicon. The arsenic diffusion depth at 1025 ºC in the Si0.95Ge0.05 epitaxy sample is enhanced by a factor of 1.26 compared with a similar Si control sample and by a factor of 1.30 in the ion beam synthesized sample. The arsenic diffusion in the Si0.95 Ge0.05 epitaxy sample is modeled by increasing the arsenic diffusion coefficient from the Si value of 1.92 x 10-15 to 5.15x10-15 cm2 s-1, and in the ion beam synthesized sample by using the same diffusion coefficient of 5.15x10-15 cm2 s-1 and increasing the "plus one" factor in the transient enhanced diffusion model from 0.01 to 1.5. Arsenic diffusion in a silicon sample implanted with 2x1015 cm-2 Si+ can be modeled using the same plus one factor of 1.5, thereby demonstrating the consistency of the modeling

Single, double and surround gate vertical MOSFETs with reduced parasitic capacitance

The vertical MOSFET structure is one of the solutions for reducing the channel length of transistors under 50nm. Surround gates can be easily realised in vertical MOSFETs which offer increased channel width per unit silicon area. In this paper, a low overlap capacitance, surround gate, vertical MOSFET technology is presented. A new process that uses spacer or fillet local oxidation is developed to reduce the overlap capacitance between the gate and the source/drain electrodes. Electrical characteristics of surround gate n-MOSFETs are presented and compared with characteristics from single gate and double gate devices on the same wafer. Transistors with channel length down to 100nm have been realised. They show good symmetry between the source on top and source on bottom configuration and subthreshold slope down to 100mV. The short channel effects of the surround gate MOSFETs are investigated