1. 7 pn Junction Diode: Small-signal Admittance
반도체 소자 연구실
박 종 태

2. small signal voltage : Va ac current : i small signal
7.1 INTRODUCTION
small signal voltage : Va
ac current : i
small signal
admittance:Y=G+jwC
Y = G +jwC
(7.1)

4. 7.2 REVERSE-BIAS JUNCTION CAPACITANCE 7.2.1 General Information
C-V characteristics of pn diode

5. (7.2) Junction or depletion layer capacitance
Charge density oscillation with a.c signal
(7.2)

6. 7.2.2 C-V Relationships (7.3) and (7.4) (7.5) Vbi→Vbi-VA
One sided power law profiles
(7.3)
and
(7.4)
(7.5)

8. Depletion region width for one sided power-law profiles
(7.6)
(7.7)
(7.8)

9. For varactor , tuning ratio
(7.9)
(7.10)

10. 7.2.3 Parameter Extraction/Profiling
Form C-V plot
Doping concentration versus position
(7.11)
(7.12)
(7.13)
Example 7.2

12. 7.2.4 Reverse-Bias Conductance
Differential dc conductance of a diode :
When the reverse bias exceed a few kT/q, G0→0
When the dc recombination-generation current dominates in the given diode,
(7.14)
(7.15)
(7.16)

13. 7.3 FORWARD-BIAS DIFFUSION ADMITTANCE 7.3.1 General Information

14. The admittance due to the minority carries charge oscillation
(7.17)

15. 7.3.2 Admittance Relationships
(7.29b)
(7.30a)
(7.30b)