This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.

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In many cases of TLS (thermal laser stimulation) measurements, wafer back grinding is needed because thinning of the wafers improves the signal strength. Figure 2809 shows the percent transmission as a function of wavelength and pdoping concentration for 625 pm of Si [1]. Heavier doping increases laser absorption and thus reduces transmission. The percent transmission of infrared wavelengths is given by [1],
 [2809]
where,
%T  The percent transmission,
r  The reflection coefficient,
α  The absorption coefficient,
d  The thickness of Si wafer.
As indicated in Equation 2809, decreasing the thickness can dramatically increase the %T and therefore the TLS signal.
Figure 2809. Percent transmission of laser intensity through pdoped Si in 625 pm thickness and having doping concentrations of (a) 1.5 x 10^{16}, (b) 3.3 x 10^{17}, (c) 1.2 x 10^{18}, and (d) 7.3 x 10^{18} cm^{3}. The 1340 nm wavelength is marked by a vertical line. [2]
[1] S. E. Aw, H. S. Tan, and C. K. Qng, “Optical Absorption Measurements of Bandgap Shrinkage in Moderately and Heavily Doped Silicon”, J. Phys.: Condens. Mutter, 3, 1991, pp. 82138223.
[2] Cole, EI; Tangyunyong, P; Barton, DL, Backside localization of open and shorted IC interconnections, 36th Annual IEEE International Reliability Physics Symposium, (1998). DOI: 10.1109/RELPHY.1998.670462.
