Question 5. Calculate the Work Function Difference Assuming a Gold (Au) Gate.

    The following figure shows the energy-band diagram of three separated components form the MOS capacitor.[1]

    For the case of using a gold (Au) gate, ΦM is the work function of metal and ΦS is the work    function of semiconductor. Thus, ΦMS is the work function difference between the gate and semiconductor. 

         (1)

    where 

 (2)

    Xs is the Electron Affinity of the Si, the value of which is 4.14 eV.

    Eg is the Bandgap energy, the value of which is 1.12 eV.

    Φfp is the Fermi potential for p-type silicon.

    According to the formula:

(3)

    Thus,

   (4)

    Therefore

  (5)

Reference:

[1]	N. Arora, MOSFET Modeling For VLSI Simulation, Singapore: World Scientific Printers, 2007.