Transfer Characteristics of an EMOSFET

An enhancement mode Mosfet's current-voltage equation in saturation mode is given by: $$I_D = \frac{\mu C_{ox}L}{2W}(V_{GS}-V_{th})^2$$

The graph:

My question: I studied that the transfer characteristics can be obtained as long a $V_D > 0$. However, isn't it incorrect to just assume that the MOSFET is in saturation?

• The formula should be MU * Cox * W /L ...... Mar 10 '18 at 17:26