REVERSE BREAKDOWN MECHANISMS
n | depletion | p · select mode below
☀ LIGHT
⚡ AVALANCHE
Impact Ionization · V > 6V · lightly doped
〰 ZENER
Band-to-Band Tunneling · V < 5V · heavily doped
Legend
Hot electron (Ec)
New electron (Ec)
Hole (Ev)
Struck e⁻ crossing Eg
Valence e⁻ target
Tunneling electron
Hole left behind
Tunnel barrier (thin Eg)
Filled valence state (p)
Empty conduction state (n)
Sequence
1
Hot e⁻ gains KE > Eg from field
2
Strikes valence e⁻ at Ev
3
Hot e⁻ slows — KE transferred
4
Struck e⁻ crosses Eg upward
5
New e⁻ at Ec, hole at Ev
6
Chain multiplication →
1
Heavy doping → thin depletion
2
Ev (p-side) aligns with Ec (n-side)
3
Quantum wavefunction penetrates barrier
4
e⁻ tunnels horizontally thru thin Eg
5
Appears in Ec on n-side
6
Hole left in Ev on p-side
Controls
Field / Bias
3.0×
Rate
4
PAUSE
RESET
—
Live Counts
e⁻ in Ec
0
h⁺ in Ev
0
Ionizations
0
Comparison
Mechanism
AV: impact ionization
ZN: QM tunneling
Voltage
AV: > ~6V
ZN: < ~5V
Temp coeff
AV: +positive
ZN: −negative
Doping
AV: light
ZN: heavy (thin W)