Noninvasive optical measurement of hole diffusion profiles in p- p + silicon homojunction is reported by ellipsometry in the terahertz (0.2-1.5 THz) and midinfrared (9-50 THz) spectral regions. In the terahertz region a surface-guided wave resonance with transverse-electrical polarization is observed at the boundary of the p- p+ homojunction, and which is found to be extremely sensitive to the low-doped p -type carrier concentration as well as to the hole diffusion profile within the p- p+ homojunction. Effective mass approximations allow determination of homojunction hole concentrations as p=2.9× 1015 cm-3, p + =5.6× 1018 cm-3, and diffusion time constant Dt=7.7× 10-3 μ m2, in agreement with previous electrical investigations.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)