Characterization ofglobal inversion layer in thin-gate-oxide deep-submicron p-MOSFETS

A simple electrical method is presented for the characterization of the inversion layer in p-channel MOSFET's with either p⁺ poly gate (surface-channel, SC) or n⁺ poly gate (buried-channel, BC). The dc centroid of the inversion layer profile, X_c, represents the effective thickness of the inversion layer in the SC device or the physical location of the buried-channel in the BC device. For the first time, it is well demonstrated that, based on the small-signal gate-to-channel capacitance measurement, the global inversion layer hole profiles in both types of p-MOSFET's can be constructed from three elements, i.e., X_c (dc centroid), X_w (band diagram characteristic width) and ΔN_inv (increment of net carrier area density).