Nondestructive one-dimensional scanning capacitance microscope dopant profile determination method and its application to three-dimensional dopant profiles

In this article, we present a new one-dimensional (1D) dopant profile deter mination method, which extends to the quantitative three-dimensional (3D) d opant profile extraction. This nondestructive method, which is different fr om the common scanning capacitance microscopy (SCM) measurement/dopant extr action, can potentially measure real metal-oxide-semiconductor field-effect transistor devices having 3D structure. Through SCM modeling, we found tha t the depletion layer in silicon was of a form of a spherical capacitor wit h the SCM tip biased. Two-dimensional (2D) finite differential method code with a successive over relaxation (SOR) solver has been developed to model the measurements by SCM of a semiconductor wafer that contains an ion-impla nted impurity region. Then, we theoretically analyzed the spherical capacit or and determined the total depleted-volume charge Q, capacitance C, and th e rate of capacitance change with bias dC/dV. It is very important to obser ve the depleted carriers' movement in the silicon layer by applying the bia s to the tip. So, we calculated the depleted-volume charge, considering dif ferent factors such as tip size, oxide thickness, and applied bias (dc + ac ), which have an influence on potential and depletion charges. Finally, we developed a 1D inversion algorithm to convert the SCM output (dC/dV) into r eal dopant concentration, comparing the SCM signal output with the calculat ed dC/dV. Using the inversion modeling, we have quantitatively extracted th e 1D dopant profile from the SCM dC/dV vs V curves. (C) 2000 American Vacuu m Society. [S0734-2101(00)15504-6].