Technical data

Module 13
SPGU Control and Applications
13-23
Basic Flash memory Cell Structure
Drain
Source
Control gate
Floating node
Bulk
V
CG
C1
Vd
C2
C3
C0
V
CG
Id
Voltage for Write/Erase judgment
Write
(Qf is injected)
Erase
(discharged)
Qf
Qf is injected (by a pulse) to
write the memory
Effective gate voltage shifts Delta Vg = Qf/Cf.
Cf is effective floating gate capacitance.
Delta Vg
Flash 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.