Investigation of the dynamics of recrystallization and anisotropic local melting of implanted silicon under irradiation by pulses of incoherent light with different duration and power densities has been carried out. Dynamics of recrystallization of implanted silicon surface has been investigated in situ using a diffraction method. The method is based on the registering of the diffraction signal from a special periodic structure with high time and spatial resolution. This periodic structure is formed using special regimes of implantation of phosphorus and silicon ions in monocrystalline silicon with different fluencies.
To study the main features of local melting more detail in situ investigations of mechanism of this effect were carried out at incoherent light irradiation with different pulse durations and irradiation power densities. These investigations were made using special long-focus microscope and high-speed camera. The results of in situ investigation of the density and sizes of local molten regions on the silicon surface are presented. In this work it was established that for all used light pulse durations the dependences of density of local molten regions on time has a similar character. Three stages are observed: (1) very fast increase from 0 (at the moment of local molten regions nucleation) up to the maximum value; (2) the plateau; (3) decrease due to coalescence of neighboring local molten regions. These results are provided that local molten regions are predominantly created during a relatively short time interval. It also has good agreement with the model of superheating of the semiconductor surface with respect to the equilibrium melting point during the pulse light irradiation.
The nucleation and growth of local molten regions (LMRs) during the light irradiation was detected using high-speed camera and long-focus microscope. In situ dependences of sizes and density (quantity per cm-2) of LMRs are interpreted in the frame of the following model. A great amount of heat is transferred to the semiconductor surface during light pulse irradiation. This proces is nonstationary and the heat is not distributed homogeneously over the thickness of the sample. As a result, a specific short-lived state is formed, in which the semiconductor surface is superheated in the solid-state phase with respect to the equilibrium melting temperature. Some surface areas, which contain the defects, begin to melt. Temperature of these local molten regions immediately decreases down to the equilibrium melting temperature. The created LMRs begin to absorb the heat from neighboring superheated solid regions. As a result, the temperature of superheated regions decreases down to the equilibrium melting point. No new local molten regions are formed and the sizes of existing local molten regions increase due to absorption of the energy of light pulse. To study the main features of local melting more detail in-situ investigations of mechanism of this effect were carried out at incoherent light irradiation with different pulse durations and irradiation power densities. The last our results agree with the superheating model. Also the dynamics of phase transitions on the surface of implanted silicon at different regimes of light pulses is investigated using high-speed camera and special diffraction gratings. The diffraction gratings were formed using ion implantation and the effect of local melting. The dynamics of diffraction during and after the light pulse irradiation was studied.
In this work the dynamics of anisotropic local melting of monocrystalline and implanted silicon at different regimes of light pulse irradiation was investigated. The results of in situ investigation of local melting of monocrystalline silicon were carried out for the first time using special long-focus microscope and high-speed camera. The time dependences of the density and sizes of local molten regions were systematically measured. We explain the increasing of the size of LMRs during short time by the superheating of the semiconductor in the solid state with respect to the equilibrium melting point. Due to superheating conditions are arisen to overcome the barrier for the formation of the liquid phase nuclei. The dynamics of anisotropic local melting of implanted silicon was investigated using several optical methods and special diffraction gratings. The intensity of diffraction picture depends on the contrast of this periodical structure, i.e. from difference of crystalline and amorphous fragments of gratings. The dynamics of diffraction effectivity during and after the power light pulse was registered using high-speed camera. Three qualitative stages: solid-state recrystallization, local melting and liquid-phase recrystallization were observed experimentally.
The mechanism and the main features of the effect of anisotropic local melting of semiconductor surfaces which can be observed at definite regimes of homogeneous irradiation by powerful pulses of coherent and incoherent light are investigated. The dynamics of this effect was studied for the first time. Using rapid filming microphotos of the silicon surface were taken. On implanted silicon, the dynamics of reflection of the probing He-Ne laser radiation under heating with powerful optical irradiation is measured. The results can be explained by the different degree of semiconductor superheating with respect to the equilibrium temperature of melting. It is demonstrated that under certain conditions light pulse itself generates centers for the formation of liquid nuclei.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.