Electrically-alterable memory using a dual electron injector structure

A novel type of electrically-alterable memory which uses the phenomenon of enhanced electron injection into SiO
2
from Si-rich SiO
2
to charge or discharge a floating polycrystalline Si storage layer in a metal-oxide-semiconductor field-effect-transistor is described. This non-volatile memory differs from others using floating polycrystalline Si in the charging or discharging process. This improvement is accomplished by using a chemically-vapor-deposited stack of Si-rich-SiO
2
-SiO
2
-Si-rich-SiO
2
between the floating polycrystalline Si layer and the control gate electrode. This device is capable of being written or erased in 5 msec at voltages of ≤ 16 V and in 2 µsec at voltages ≤ 23 V with excellent charge retention.