Evaluation of the effective threshold energy of the Interband impact ionization in a deep-submicron silicon n-channel MOS transistor

Using the ensemble Monte Carlo method allowing for the main features of charge-carrier transport in conditions of strong electric fields, a deep-submicron silicon n-channel MOS transistor with a channel length of 50 nm is simulated. In the Keldysh impact ionization model with a soft threshold in a channel of the simulated transistor, the effective threshold energy of this process is calculated.     

Contact TiSi2and Barrier TiN Layers for ULSI Multilevel Metallization

TiSi₂and TiN thin films are deposited with the surface-diffusion reactions of titanium with silicon and nitrogen, respectively. It is demonstrated that the deposition of a TiSi_1.3alloy onto an Si substrate heated to 675°C produces a low-resistivity TiSi₂film. At the same time, a silicide film forms on SiO₂. This film can be distinguished from the disilicide on Si for the purpose of total selective etching. Special process conditions are determined for the fabrication of homogeneous polycrystalline TiN films with a columnar structure and low resistivity (25–35 cm)     

Evolution of the Co–N/Ti/Si System in Magnetron Sputtering of Co onto a Heated Ti/Si(100) Substrate

The surface-diffusion interaction is studied experimentally between cobalt and a heated Ti/Si(100) substrate under reactive magnetron sputtering in an argon–nitrogen atmosphere. A model is proposed that accounts for the nature of silicide formation in the Co/Ti/Si system by volume and surface-diffusion reactions between cobalt and the substrate. It is shown that the diffusion of cobalt into the silicon is impeded by the TiSi _x layer to a far greater extent than by the Ti layer.     

Computer Simulation of a Nanoscale Ballistic SOI MOSFET with a Sub-10-nm Si Layer

A physical model and a computer simulation program for nanoscale ballistic SOI MOSFETs are developed. The model includes transistor parameters such as the type and level of doping in the source and drain regions, gate length, Si and gate-oxide thicknesses, spacer length, gate-material work function, etc. Transistor performance is characterized in terms of transconductance, subthreshold slope, on- and off-state drain currents, gate–source overlap capacitance, etc. The software enables one to optimize the transistor parameters.     

Operation of an electronic lithograph in the mode of a scanning electron microscope

The operation of the Raith-150 electronic lithograph in the mode of a scanning electron microscope is examined. Sizes of the pixel and effective diameter of an electron probe are determined along both scanning directions. The parameters of a system for scanning and forming the lithograph??s electron probe compare well with those of the best scanning electron microscopes.     

Effect of Surface Roughness on Quantum Carrier Transport in Ultrathin Films

A theoretical study is reported of the carrier transport in an ultrathin metal film and a quantum-well layer subject to scattering by surface irregularities. A consistent quantum-mechanical approach to the problem is developed. Power-law approximations with different exponents are obtained to the conductivity–thickness relationship. The results are compared with previously published experimental data.     

New method for the Langmuir probe diagnostics of polymerizing plasmas

A pulsed Langmuir probe method of plasma diagnostics is proposed and validated for low-pressure, high-density, low-temperature plasmas capable of producing a nonconducting film on the probe surface. The method essentially involves cyclic probe-surface cleaning by ion bombardment. A switching pattern of probe potential is designed, taking into account the mechanism by which a space-charge region is formed near the probe. The method is successfully employed in an experiment on inductively coupled CHF₃ and Ar plasmas. The results of the experiment are presented.     

Paramagnetic-center detection by SQUID measurement of static magnetic susceptibility

A method is proposed for counting small numbers of impurity paramagnetic centers in semiconductor specimens. It involves SQUID measurement of static magnetic susceptibility under resonant microwave saturation of the magnetic sublevels. The ultimate sensitivity of the method is calculated and compared with those of other approaches.     

Effect of a transverse applied electric field on electron drift velocity in a GaAs quantum wire: A Monte Carlo simulation

A Monte Carlo simulation is run to study the electron transport in a thin undoped GaAs quantum wire under the influence of a transverse applied electric field. Phonon and surface-roughness scattering are included. Electron drift velocity is investigated as a function of roughness amplitude at a temperature of 77 or 300 K and a longitudinal electric field of 10⁴ or 10⁵ V/m. A transverse applied field is shown to provide a means of controlling drift velocity, affecting the scattering rate.