CHARACTERIZATION AND MODELING OF THE N-CHANNEL AND P-CHANNEL MOSFETS INVERSION-LAYER MOBILITY IN THE RANGE 25-125-DEGREES-C

We present an accurate, yet simple, engineering mobility model for bot h n- and p-channel MOSFETs. It is found that for devices with bulk con centration (N(A) or N(D)) less-than-or-equal-to 5 x 10(16) cm-3 and ox ide charge density (Q(ox)/q) less-than-or-equal-to 5 x 10(10) cm-2, th e effect of coulomb scattering on the channel mobility is insignifican t and the mobility degradation is dominated by the phonon and surface roughness scattering modes. However, as substrate impurity concentrati on increases (N(A) or N(D) greater-than-or-equal-to 10(17) cm-3) for s ubmicron CMOS devices, the mobility degradation with the transverse el ectric field is affected by both the coulomb scattering and the phonon scattering in the low field region, and by the surface roughness scat tering in the high field region. The effective channel mobility for se veral CMOS devices is determined using a modified split C-V method tha t takes into account the gate- and drain-bias dependence of the invers ion charge. With this new measurement technique, the extracted mobilit y data are shown to be independent of drain voltage (\V(DS)\ = 20-100 mV) used in the I(DS)-V(GS) measurements. Good agreement between model ed and experimental results is observed over a wide range of biases, o xide thicknesses, doping concentrations and temperatures.