Question

Si has 6 equivalent conduction bands. Through additional engineering we will learn later on, we can make the two conduction band minima located on the [001] axis move down compared to the four other conduction bands, by a small amount AEc. 1. Write down an expression of electron concentration in terms of Fermi level Ef, conduction band level Ec, which is the Ec of the lowest conduction band minima, the transverse and longitudinal effective masses mi and mt, temperature T and Planck's constant h or Assuming ??,?3KT, such that virtually the higher energy conduction bands are empty, determine the conduction effective mass in terms of mi and mt for an electric field E that is applied along the [100] direction. You will need to take the average of this for all bands, as we did in our mid term exam. Continuing, assuming mean free time is the same as in regular Si, how much mobility change do you expect in the previous questioni? - - _ 2. 3.

Answer 1

Nuober d厂 Eleckoy un Corduclion -Gad un tun E5 -follooing Poind be liseas 3) fermt ec s CE-EF 2. dI ec

KT. EC に个 ec da Kt €.rec , γ-o b ahon E=ao , 12co 1136