摘要:

The two‐dimensional (2D) redistribution of impurities in semiconductors is an important step for the research and fabrication of modern very large scale integrated (VLSI) circuits. The diffusion profiles must be known precisely if one is to master and model correctly the operations of integrated circuits. Many two‐dimensional (2D) simulators for processing bulk silicon do actually exist; however, they are not general enough to be able to simulate these processes on other structures, e.g., SOI (silicon on insulator). In this paper we present a two‐dimensional (2D) analytical solution of the diffusion equation for the case of the SIMOX (separation by implanted oxygen) structure. The model developed takes into account the limiting conditions associated with this material as well as the initial ion implantation profile. The program has been developed in this way and will be included in a complete 2D simulator for SOI process. As an example, we simulate the formation of the isolation zone in the SIMOX structure, i.e., the implantation and redistribution of boron during the formation of field oxide.

ISSN:0021-8979    

DOI:10.1063/1.340345

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The formation of dark field ion images by scattered secondary ions is proposed. It is shown that this model can account for various dark field observations, and that it can be used in the determination of surface feature inclinations. Its use in the estimation of topography‐induced bright field intensity contributions is also demonstrated.

ISSN:0021-8979    

DOI:10.1063/1.340346

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

It is found that, like the directly transmitted radiation field previously investigated, an internally multiply reflected radiation field can also become an electromagnetic missile under certain different electromagnetic‐missile conditions. The analysis is carried out in a general way, i.e., for the point source located either inside or outside the dielectric sphere. The electromagnetic‐missile conditions are obtained for general multiply reflected radiation fields.

ISSN:0021-8979    

DOI:10.1063/1.340347

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

An exact wave‐optics analysis of wave propagation in thin‐film optical waveguide with gyrotropic and anisotropic materials as waveguide film or substrate is presented for the first time. Based on the field equation and the boundary conditions of the guide, the field distribution and phase velocity of the eigenmodes of the guide are determined, and the differences in characteristics due to waveguide structure are examined in detail. The relation for TE‐TM conversion is derived in the form of the Jones matrix which allows a direct interpretation in the conversion efficiency of the guide.

ISSN:0021-8979    

DOI:10.1063/1.340348

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Self‐generation of spatial subharmonics when two coherent, almost collinear, pump beams propagate in a nonlinear photorefractive crystal of Bi12SiO20, is reported. The intensity of the self‐generated light beam at the half‐angle between the two pumps is as high as 40% of the pump beam intensity. This phenomenon is probably a spatial analog of the temporal subharmonics obtained in a cavity containing a nonlinear medium. Application of the subharmonic of half‐spatial frequency to collinear Bragg diffraction of a near infrared beam is demonstrated.

ISSN:0021-8979    

DOI:10.1063/1.340349

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A transverse flow cw atomic iodine laser at 1.315 &mgr;m excited by the photolytic pumping of C3F7I and demonstrating virtually an unlimited operating time is reported. The use of transverse flow establishes a much more constant integrated gain along the optical axis than that previously reported for the longitudinal flowing cw atomic iodine laser. Consequently, a cw atomic iodine laser is achieved having a greatly improved amplitude stability and easier operation in only the fundamental TEM00transverse mode. Such an operation makes this type of cw atomic iodine lasr much more useful as a diagnostic probe laser at 1.315 &mgr;m than the previously reported longitudinal device.

ISSN:0021-8979    

DOI:10.1063/1.340299

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Theoretical basis is developed for the sphere‐resonance method to determine elastic constants of a very small crystal. In this method, a sphere of crystal is formed, and frequencies of its free oscillations are measured by the resonance method. To calculate frequencies of the sphere, we use the Rayleigh–Ritz (variational) method as in the rectangular parallelepiped resonance method developed by Ohno [J. Phys. Earth24, 355 (1976)]. It is necessary in the Rayleigh–Ritz method to evaluate matrix elements which are quadratic forms in the strain tensor with coupling by the elastic tensor. To do this the elastic tensor is transformed to spherical coordinates, and the contravariant canonical components of the elastic tensor are expanded by the generalized spherical harmonicsYNmlwith nonzero coefficients only forl=0, 2, 4. For seven crystal systems, properties of the matrix elements are examined, and free oscillations are classified. We also obtain selection rules for excitation which are useful for the mode identification.

ISSN:0021-8979    

DOI:10.1063/1.340300

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

It is shown that Langmuir probes can have three different floating potentials in plasmas produced by a hot filament discharge in a multi‐dipole device when the primary and secondary electron currents are comparable. The measured floating potential depends on the probe’s initial condition—the most negative and the least negative potentials are found to be stable and the in‐between value is found to be unstable. Results are compared to a simple theoretical model.

ISSN:0021-8979    

DOI:10.1063/1.340301

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Two small ion sources have been used to generate positive nitrogen ion beams. One is a multicusp ion source, the other is a compact microwave ion source which needs no magnetic field for operation. Both sources are operated with and without a magnetic filter to control the energetic electron population near the extraction region. Results for both ion sources, including current densities and ionic species mix are presented. The multicusp ion source can produce beams of nitrogen ions with greater than 90% of the ion species either N+or N+2with current densities of ∼8 and 2.5 mA/cm2, respectively. The microwave ion source can generate nitrogen ion beams composed of more than 85% N+2with current densities of ∼30 mA/cm2.

ISSN:0021-8979    

DOI:10.1063/1.340302

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The low‐pressure mercury‐argon discharge was analyzed employing a two‐temperature representation of the electron energy distribution. The electron energy distribution function was approximated with two Maxwellian portions, which represented a low‐energy part of the electrons (bulk) characterized by higher temperature and a high‐energy part of the electrons (tail) characterized by lower temperature. As a parameter representing non‐Maxwellian distribution, the ratio of the tail temperature to the bulk temperature was introduced. The ratio was determined experimentally by adjusting the calculated field strength of the positive column to the observed one. The plasma parameters under the two‐temperature approximation were shown to be obtainable by solving the rate equations for the particle densities and the energy balance equation for the whole electron group. The model was applied to the positive column of a 24‐mm‐diam tube. The rate coefficient of Hg 61S0to Hg 61P1transition was found to be 0.64 times that obtained under the Maxwell approximation.

ISSN:0021-8979    

DOI:10.1063/1.340303

出版商:AIP    

年代:1988

数据来源: AIP