SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

154 CHAPTER 4. JUNCTIONS IN SEMICONDUCTORS:P-NDIODES

0

p-type n-type

Structure

Charge density

–Wp

Wn

m

Electric field

Wn

Charge neutrality in

the depletion region:

WpNa=WnNd

–Wp Wn

–Wp

+++

+++

+++

– ––

– ––

– ––

0

0

Electric field peaks

at the junction

x

x

E

Figure 4.4: Thep-nstructure, with the charge and the electric field profile in the depletion region.
The electric field peaks at the junction as shown.