380 CHAPTER 8. FIELD EFFECT TRANSISTORS
eφb
EF, m ΔEc
E -eVG
F, s
eV 2
eV 1
eVdi-
- d -ds^0 Δd
eVdi+
Z
Z
nm npar
ns
Nd+
Z
- 1 =-enεm
2 =
ens
ε
- d -ds^0 Δd
(a)
(b)
(c)
(d)
Gate
Metal
{ {
AlGaAs GaAs
δ Layer-doped 2DEG
- d -ds^0 Δd
dδ
D
E
E
E(z)
Figure 8.15: (a) Schematic diagram of aδ-doped AlGaAs/GaAs MODFET, along with (b) the
charge distribution, (c) the band diagram, and (d) the electric field distribution in the structure.