PEREC PN junction with voltage applied in the forward direction 16
Power Electron cs i 16 PN junction with voltage applied in the PN junction with voltage applied in the forward direction forward direction V + + + + + - - - - - n p Wo W + -
PN junction with voltage applied in the reverse direction Effective direction of electronic field 17
Power E l ect r o n cs i 17 PN junction with voltage applied in the reverse PN junction with voltage applied in the reverse direction direction - + V + + + + + - - - - - - - - + + + n p Wo W Effective direction of electronic field
PEREC Construction of a practical power diode Anode p Na =10 cm 10 u m n epi No=10 cm Breakdown voltage dependent n substrate Nd=10 cm 250μm Cathode 4 Features different from low-power(information electronic)diodes Larger size Vertically oriented structure drift region(p-i-n diode) Conductivity modulation 18
Power Electron cs i 18 Construction of a practical power diode Construction of a practical power diode Features different from low Features different from low-pow er (information electronic) diodes r (information electronic) diodes – Larger size – Vertically oriented structure – n drift region (p-i-n diode) – Conductivity modulation 250 μ m Breakdown voltage dependent p 10 μ m n substrate Nd =10 cm 19 -3 Na =10 cm + 19 -3 n epi Nd =10 cm 14 -3 p n substrate Nd =10 cm + 19 -3 Na =10 cm + 19 -3 n epi - Nd =10 cm 14 -3 i Anode Catho d e + - V -
PEREC Forward-biased power diode conductivity modulation Oo minority carrier in/ection
Power Electron cs i 19 Forward Forward -biased power diode biased power diode
PEREC Reverse-biased power diode oYd零 is cocensetrtieas E depletion regioN, relerse hisseD 串 Breakdown Avalanche breakdown Thermal breakdown
Power E l ect r o n cs i 20 Reverse Reverse-biased power diode biased power diode Breakdown Breakdown – Avalanche breakdown – Thermal breakdown