Agilent Technologies B1500A Training Manual page 107

Flash Memory
Basic Flash memory Cell Structure
V
CG
Vd
C2
Qf
C3
C0
Drain
Bulk
Qf is injected (by a pulse) to
write the memory
Flash memory is one type of floating gate memory. The left figure shows the structure of the floating
gate memory cell. There is a metal floating node on the top of transistor channel region. Any stored
charge in this floating node shifts its threshold voltage as shown in the right figure.
Control gate
Id
Floating node
C1
Source
Effective gate voltage shifts Delta Vg = Qf/Cf.
Cf is effective floating gate capacitance.
13-23
Erase Write
(discharged) (Qf is injected)
Delta Vg
V
CG
Voltage for Write/Erase judgment
Module 13
SPGU Control and Applications