CHARACTERIZATION OF DELTA-DOPED SILICON BY ELECTROLYTE ELECTROREFLECTANCE

In a commercial MBE system delta-doped silicon layers are prepared fol lowed by epitaxial growth of undoped cap layers. For the characterizat ion of these structures the electrolyte electroreflectance technique i s used in connection with successive layer removal by anodic oxidation . The measurements are carried out in the range of the complicated 3.4 eV structure. In the high-energy region of the electroreflectance spe ctra the lineshape is independent of electric field and the amplitude of the 3.46 eV peak follows the derived dependences on de bias, modula tion voltage, and cap layer thickness. It is shown that this peak is a suitable optical probe to localize the delta-layer and to determine i ts areal doping density.