On the universality of inversion layer mobility in Si MOSFET's: Part I-effects of substrate impurity concentration

Abstract

Abstract-This paper reports the studies of the inversion layer mobilities in n-channel MOSFET's fabricated on Si wafers with three surface orientations ((loo), (110), and (111)) from the viewpoint of the universal relationship against the effective field, E,R(= q(A\-clpl + 11 . -Vh)/~Si). It is found that the universality does hold for the electron mobilities on (110) and ( l l l ) , when the value of 17 is taken to be 113, different ftom the electron mobility on (loo), where I ) is 1/2. Also, the E,ff dependence of the electron mobility is found to differ among (loo), (110), and (111) surfaces. This is attributed to the differences in the E v~ dependence of the mobility limited by surface roughness scattering among the orientations.The origins of E, m and '1 are discussed on the basis of the relaxation time approximation for a 2DEG (2-dimensional electron gas). While the surface orientation dependence of 11 in phonon scattering can be understood in terms of the subband occupation, it is found that the theoretical formulation of surface roughness scattering, used currently, needs to be refined in order to explain the differences in E,ff dependence and the value of 11 among the three orientations.

Simulation of Magnetotransport in Hole Inversion Layers Based on Full Subbands

“…1 the simulated zero magnetic field mobilities of unstrained Si bulk pMOS transistors are shown, which reproduce the measurements from [5] for (100) and [6] for (110) surface orientations very well. The effective mass (Fig.…”

On The Modeling Of CV Data For State-Of-The-Art CMOS Technologies: Do We Need To Include Fast Interface States?

“…2) yields a capacitance which is far too high below threshold. In addition, the characteristic capacitance signature of the IS is not found in the original split-CV data of [5] (Fig. 4), nor does it appear in the split capacitance of devices recently fabricated at Fujitsu (Fig.…”

“…Including this IS distribution the model turns out to be incompatible with our experimental results. Moreover in [7] the authors propose an IS model for the devices measured in [5] in order to reconcile their results with the ones of [5]. But also this IS density (curve TA in Fig.…”

“…Therefore, the mobilities extracted from drain current data under the assumption that all channel charge is mobile are too low. Thus the quality of the de-facto standard mobility-field relation for MOSFETs (see for example [5]), with which nearly all current device simulation models have been calibrated, becomes questionable [2]. In this work an independent evaluation of these effects is attempted.…”

Modeling Hole Surface- and Bulk-Mobility in the Frame of a Spherical-Harmonics Solution of the BTE

“…As for the surfaceinduced scattering mechanisms, namely, surface-roughness, surface acoustic phonons and charge centers at the interface, we use a two-dimensional description of the carriers (i.e., holes) in the region where a quantum confinement occurs, and compute the corresponding scattering terms. We calculate the inversion-layer hole mobility in a Si MOSFET, consistently with [4], and compare the inversion-layer mobility vs. effective electric field with experimental data. Results show that the SHE code successfully reproduces the universal behavior of the effective hole mobility.…”