SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

4.3. CURRENT FLOW: P-N DIODE UNDER BIAS 161

p n

Wp 0Wn

n( x) p( x)

np pn

Depletion Region

mi no rity char ge

(a)

(b)

(c)

np+np

pn+pn

Total current

Electron current

Electron current

position

(minority) Hole current

(minority)

Hole current

δn( x) = n( x) np δp( x) = p( x) pn

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    Figure 4.7: (a) A schematic showing thep-nstructure under forward bias. (b) The minority
    carrier distribution (c) Minority and majority current.