NVM Memory Principles
X-FAB supports various memory principles covering Zener zaps, Poly fuses, Floating gates and SONOS architecture. Below the characteristics and typical use cases are described accompanied by schematic cross section images.
Zener Zaps
Technology independent zener diode device.
Write
- melting of pn-junction
- destroying the device
Erase
- impossible
Usage
- for trimming purposes
Poly Fuses
Write
- external programming voltage supplied via pad
- device resistance is increased
Erase
- no re-programming / erase possible
Usage
- for trimming purposes
Floating Gate
Programming
- Fowler-Nordheim Tunneling
Erase
- Fowler-Nordheim Tunneling
Usage
- for EE-Latches, EEPROM, CEEPROM
Floating Gate
Programming
- Hot carrier injection
Erase
- UV light (on wafer level)
Usage
- OTP, trimOTP
SONOS
Programming
- modified Fowler-Nordheim tunneling
- electrons stored inside the nitride
Erase
- direct Fowler-Nordheim tunneling
- remove electrons from the nitride
Usage
- for EEPROM, NVRAM, Flash
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