Determination and Study of MOSFET Technology Current

CMOS Technology Dependent Current (I0) is a transistor parameter needed to define the inversion coefficient of the transistor. Designers using the gm/ID design methodology may determine I0 directly from the EKV model parameters. The paper proposes a simple algorithm for finding I0 from semiconductor foundries that support any MOSFET models, such as BSIM3 and PSP. Through the repeated use of this method the paper resolves several fundamental questions related to the use of the technology current in CMOS analog design. It is shown that I0 is bias and process dependent. The paper studies the dependence of I0 on VDS and L. The impact of process corners on I0 tolerances and on the design performance is also studied. It is demonstrated that such tolerance effects may be significant even in a simple amplifier circuit. Yet it is shown that the assumption of a constant I0 that significantly simplifies submicron CMOS analog design has no adverse impact on the accuracy of the design. The paper also shows that the transconductance efficiency vs. inversion coefficient MOSFET curve is not affected by process corners thus providing an additional substantiation to the claimed universality of such MOSFET curves. The paper results pave the way to the use of Binkley's Operating Plain design method for transistor models that are other than the EKV model. 1