摘要:

Many features involved in the problem of heat flow through a semifinite metal sample irradiated with nanosecond laser pulses are discussed with reference both to the underlying physics and to the numerical solution of the heat diffusion equation.

ISSN:0033-7579    

DOI:10.1080/00337578208222830

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

To prove the feasibility of flash-lamp annealing of ion-implanted silicon, theoretical and experimental investigations have been performed. Detailed temperature calculations indicate that depending on the pulse length two different time-temperature regimes exist. In the heat conduction regime only the near surface region of the wafer is heated up to the necessary temperature and the annealing takes place in a time comparable to the pulse length. In the heat radiation regime the whole volume is heated nearly uniformly up to a maximum temperature and the heat is stored for a longer time. The thermally induced stiesses in the wafer are also calculated and compared to the temperature dependent yield stress. The basic experimental results have been obtained using As-implanted ⟨100⟩-silicon. The pulse length of the flash was 10 ms corresponding to an annealing in the heat radiation regime. The samples have been analyzed by Rutherford backscattering, sheet resistivity measurements and transmission electron microscopy. It has been found that the annealing characteristics are similar to that of conventional thermal annealing.

ISSN:0033-7579    

DOI:10.1080/00337578208222831

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

High fluence energy pulses in the nanosecond-microsecond time range involving the melting of a surface layer have been demonstrated as a very successful tool in annealing ion-implanted semiconductors. As an alternative method, longer annealing time in the 50 microsecond to 100 millisecond range can be used by supplying the necessary energy by a series of multiple scans of an electron beam or incoherent light flash. In, this case the annealing can take place via solid phase epitaxial regrowth of the damaged layer.

ISSN:0033-7579    

DOI:10.1080/00337578208222832

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A pulsed electron beam generator has been developed with an energy density adjustable between 0.3 and 5 Joules/cm2, a pulse length of about 300 nsec and with a maximum electron energy variable between 10 and 25 keV. Pulsed Electron Beam Annealing (PEBA) has been successfully applied to ion implanted semiconductors, simple metals, compounds and amorphous thin films. Results are compared to those obtained with pulsed laser beam annealing and furnace annealing.

ISSN:0033-7579    

DOI:10.1080/00337578208222833

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Ion Implantation, Laser and Electron-beam Treatment (LET) of metals have been employed extensively to produce metastable surface alloys. Recent published work on implanted alloys is reviewed first. The dilute implanted alloys (solute concentration <10 at. %) are shown to lead to crystalline metastable solid solutions. At higher solute concentrations, an amorphous phase has been observed for several binary systems and recently for a ternary system. The physical mechanisms at play, are discussed in detail. A review of the surface alloys produced by LET of metals is then presented—with an emphasis on the mechanisms involved. In particular, general criteria governing formation of metastable solid solutions under LET are proposed and shown to have excellent agreement with available data on metals and Si.

ISSN:0033-7579    

DOI:10.1080/00337578208222834

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Polycrystalline Si layers 100 to 800 nm thick have been deposited on Si single crystal substrates by CVD and annealed with a Q-switched ruby laser at energies up to 1.5 J/cm2. The optical characteristics of these layers have been measured by SEM and ellipsometry. The results can be attributed to a change in surface roughness with film thickness and laser energy.

ISSN:0033-7579    

DOI:10.1080/00337578208222835

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Lead films of thickness 100 Å, 250 Å. and 350 Å were vacuum deposited on AI and laser treated in air using single pulses (7 ns FWHM) from a Nd: glass laser operating in TEM00mode, at peak energy densities of 1.5-5.0 J/cm2. Rutherford back-scattering of 1.8 MeV He+ions was employed to determine the depth profiles of Pb in Al. Up to about 1.4 J/cm2, we observe only evaporation loss of Pb and formation of Pb-rich cells on the surface. At higher energies, liquid phase diffusion of Pb is observed up to 4 J/cm2, beyond which convection effects are seen. A quantitative analysis of data for 350 Å film at 3.0 J/cm2shows evidence of nonequilibrium segregation effects.

ISSN:0033-7579    

DOI:10.1080/00337578208222836

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

We report the first observation of non-equilibrium redistribution effects during laser treatment of a binary system having equilibrium segregation coefficient, k0, much greater than unity. Polycrystalline aluminium samples implanted with 30 keV Sb+ions to a dose of 1.7 × 1017ions/cm2were irradiated with single pulses (7 ns FWHM) from a Nd: glass laser operating in TEM00mode. The peak energy density (at the centre of the laser spot) varied from 2.0 to 5.7 J/cm2. A detailed liquid phase diffusion analysis, explicitly incorporating rapid melt front motion and interfacial segregation, is performed to fit the Sb depth profiles measured with a nuclear microprobe. An effective distribution coefficient k = 1 (as compared to equilibrium value of k0∼7) is obtained in agreement with the theoretical limiting value for large melt front velocities.

ISSN:0033-7579    

DOI:10.1080/00337578208222837

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

(100) Silicon wafers implanted with 2 × 101531P+/cm2at 100 keV have been annealed using a scanning beam of incoherent light. The main results obtained after annealing are: (a) the carrier concentration profile shows a complete dopant activation without diffusion of the implanted ions; (b) the values of carrier mobility are similar to those obtained by furnace annealing; (c) an improvement of minority carrier diffusion length is often observed; (d) a very good damage recovery is obtained. Transmission Electron Microscopy observations show that the residual damage is confined within a region at 0.2 μm depth and consists of dislocation loops of about 50 Å diameter. It is concluded that this technique can be used to obtain very good annealing of implanted layers.

ISSN:0033-7579    

DOI:10.1080/00337578208222838

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This paper describes the design features and beam measurements of a 75 J pulsed Relativistic Electron Beam Source (REB) developed at this centre. The system consists of a Marx type pulsed power source, a field emission diode and a drift column. A pulsed beam of 250 keV, 2.0 kA and 120 ns was generated and characterised.

ISSN:0033-7579    

DOI:10.1080/00337578208222839

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor