Temperature Dependence of Photoluminescence Spectra from Crystalline Silicon

Abstract

Photoluminescence (PL) spectra from lightly boron (B) doped p − -Si(100) under 488.0 nm Ar + ion laser excitation over the temperature range of 22 K-290 K is presented. Change of PL peak height (maximum intensity), peak position, peak area (areal intensity), full-width-at-half-maximum (FWHM: peak width) were determined as a function of temperature. PL intensity was sharply decreased with temperature increase in the temperature range of 22 K -170 K and then slowly increased again in the temperature range of 170 K-290 K. Phonon replicas of a relatively sharp band-to-band (or band edge (BE)) PL peak were clearly measured at low temperatures (≤90 K). PL spectra became broader and the phonon replicas were barely distinguishable as the temperature was increased. The envelope of the main PL peak and the broadening of peak width with the Si temperature were qualitatively in good agreement with the Maxell-Boltzmann probability distribution function. The direction of peak position shift with Si temperature change was also in good agreement with the temperature dependence of the Si bandgap. All measured PL spectra were curve fitted using combinations of modified Gaussian function(s) and standard Gaussian function(s). A simplified curve fitting method for broad PL spectra, consisting of the BE peak and band tail peak, using an exponentially modified Gaussian (EMG or ExGaussian) function and a number of standard Gaussian functions, was proposed from a practical usage point of view. Radiative recombination processes in Si and potential industrial applications of the PL characterization technique were discussed. For the characterization of electrical behaviors of Si, resistivity, carrier concentration, mobility and Hall effect measurements were routinely inspected during wafer fabrication and incoming quality control at the wafer fabs.1 A number of noncontact characterization techniques, such as microwave detected photoconductance decay (μ-PCD)1,2 and inductively coupled quasi-steady-state photoconductance (QSSPC), 1,3 have been used for in-line monitoring of contamination and process induced modulation of electrical behaviors of Si. Steady state PCD measurement techniques 4 enabled by improved laser technology were recently introduced.With the introduction of photoluminescence (PL) imaging and spectrum analysis, a noncontact, purely optical technique is now available for spatially resolved electrical characterization. For industrial applications, the ease of measurement without special sample preparation is important. This is especially true for in-line monitoring applications in semiconductor device manufacturers. PL measurements at room temperature (RT) are preferred. However, the RTPL spectra from Si are generally very broad and it is difficult to identify the origin of variations in RTPL spectra. In this paper, temperature dependence of PL spectra from lightly boron (B) doped p − -Si(100) was measured in the temperature range of 22 K-290 K and the effect of temperature on the change of PL spectra was investigated. Practic...

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Evidence of Silicon Band-Edge Emission Enhancement When Interfaced with SiO2:Er Films

“…25, sample F). The utilized process yields a compressive stress of about 20 MPa in the Si [25]. The Raman shift relative to stressfree Si was determined to be  = +0.14 cm 1 at an excitation wavelength of 457 nm (~290 nm probe depth) [25].…”

“…2a of Ref. 25, sample F). The utilized process yields a compressive stress of about 20 MPa in the Si [25].…”

“…The utilized process yields a compressive stress of about 20 MPa in the Si [25]. The Raman shift relative to stressfree Si was determined to be  = +0.14 cm 1 at an excitation wavelength of 457 nm (~290 nm probe depth) [25]. The (001)-plane biaxial compressive strain is estimated from the expression  || = c using the experimentally determined value of c  1.33  10 3 cm [26], yielding  ||  2 10 4 .…”

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