SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

8.5. CHARGE CONTROL MODEL FOR THE MODFET 379

0.0

0.2

0.4

0.6

0.8

0.0 0.3 0.6 0.9 1.2 1.5

Drain voltage (V)

Drain Current (A/mm)

Vgs=0.4 --- -0.8 V

(0.2 Vstep)

(a)

(b)

Figure 8.14: (a) Cross sectional SEM image of a state-of-the-art InP-based HFET device. Also
shown is a diagram indicating the device layer structure, as well as a microscope image of a
circuit made up of these devices. (b)I-Vcharacteristics of the device. Images courtesy of T.
Enoki, NTT.