1. A process for manufacturing a semiconductor memory device comprising the formation, in a same semiconductor material chip, of at least:
a first memory cell comprising a MOS transistor with a first gate electrode and a second gate electrode superimposed and respectively formed by definition in a first and a second layer of conductive material;
a second memory cell shielded by a layer of shielding material for preventing the information stored in the second memory cell from being accessible from the outside; and
wherein said second memory cell comprises a MOS transistor with a floating gate electrode formed simultaneously with the first gate electrode of the first cell by definition of said first layer of conductive material, and wherein said layer of shielding material is formed by definition of said second layer of conductive material.
2. The process according to claim 1 wherein said first and second layer of conductive material comprise each a layer of polysilicon.
3. The process according to claim 2 wherein said first cell is a double polysilicon level EPROM memory cell.
4. The process according to claim 2 wherein said first cell is a double polysilicon level Flash EEPROM memory cell.
5. The process according to claim 2 wherein said first cell is a double polysilicon level EEPROM memory cell.
6. The process according to claim 2 wherein said second cell is a single polysilicon level EPROM memory cell.
7. The process according to claim 2 wherein said second cell is a single polysilicon level Flash EEPROM memory cell.
8. The process according to claim 2 wherein said second cell is a single polysilicon level EEPROM memory cell.
9. The process according to claim 1 wherein said layer of shielding material has a variable shape.
10. The process according to claim 1 wherein said layer of shielding material is contacted and biased by low-resistance lines.
11. A semiconductor memory device comprising, in a same semiconductor material chip:
a first memory cell including a MOS transistor with a first gate electrode and a second gate electrode superimposed on each other and respectively formed by a first and a second layer of conductive material;
a second memory cell including a MOS transistor having a floating gate electrode formed by said first layer of conductive material, the second memory cell shielded by a layer of shielding material, formed by said second layer of conductive material.
12. A method for producing a shielded non-volatile memory device comprising the steps of:
forming a first non-volatile memory cell on a semiconductor substrate, the first non-volatile memory cell having a first polysilicon gate layer;
forming a second non-volatile memory cell on the semiconductor substrate, the second non-volatile cell having first and second polysilicon gate layers; and
covering the first memory cell with a shielding polysilicon layer.
13. The method of claim 12 wherein the step of forming a second nonvolatile memory cell includes:
forming a tunnel oxide layer on the semiconductor substrate;
covering the tunnel oxide layer with the first polysilicon gate layer of the second non-volatile memory cell;
covering the first polysilicon gate layer of the second non-volatile memory cell with an intermediate dielectric layer; and
forming the second polysilicon gate layer of the second non-volatile memory cell over the intermediate dielectric layer.
14. The method of claim 12 wherein the step of forming a second non-volatile memory cell includes:
forming a first dielectric layer on the semiconductor substrate;
covering the tunnel oxide layer with the first polysilicon gate layer of the second non-volatile memory cell;
covering the first polysilicon gate layer of the second non-volatile memory cell with an intermediate dielectric layer; and
forming the second polysilicon gate layer of the second non-volatile memory cell over the intermediate dielectric layer.
15. The method of claim 12 wherein the step of covering the first memory cell includes forming a shielding layer at the same time the second polysilicon gate layer of the second non-volatile memory cell is formed.
16. A process for forming a semiconductor memory device comprising:
on a semiconductor substrate, forming a dielectric layer for a first non-volatile memory cell and a second non-volatile memory cell;
forming a gate layer on the dielectric layer for the first and second memory cells;
covering the gate layer with an intermediate insulating layer for the first and second memory cells;
forming a shielding layer on the dielectric layer of the first memory cell; and
forming a control gate on the dielectric layer of the second memory cell.
17. The method of claim 16 wherein the step of forming a gate layer includes depositing a first polysilicon layer on the dielectric layer.
18. The method of claim 16 wherein the steps of forming a shielding layer and forming a control gate are performed simultaneously.
19. The method of claim 18 wherein the steps of forming a shielding layer and forming a control gate include depositing a second polysilicon layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method, performed by a user station (STA), for operating in a first social network, the method comprising:
receiving a first beacon from a device in the first social network;
synchronizing to the first social network based on time synchronization information in the first beacon;
transmitting the time synchronization information of the first beacon to a second social network, a portion of a coverage area of the second social network being outside a coverage area of the first social network;
detecting a second beacon transmitted from the second social network;
extracting discovery information from the second beacon to determine a discovery window of the second social network, the discovery information being included in the second beacon as an information element (IE);
discovering devices of the second social network, subsequent to transmitting the time synchronization information of the first beacon, using the discovery information included in the IE extracted from the second beacon; and
communicating with discovered devices of the second social network using the discovery information of the second beacon.
2. The method of claim 1, wherein transmitting the time synchronization information of the first beacon comprises:
transmitting the time synchronization information of the first beacon during the discovery window of the second social network.
3. The method of claim 2, further comprising:
synchronizing to the second social network, using time synchronization information extracted from the second beacon, responsive to determining that channel conditions in the first social network have deteriorated below a threshold.
4. The method of claim 2, further comprising:
transmitting the time synchronization information of the second beacon to devices in the first social network.
5. The method of claim 1, wherein communications in the first social network occur over a Wi-Fi Peer-to-Peer (P2P) social channel.
6. The method of claim 1, wherein the time synchronization information of the first beacon includes time stamp information for a synchronization point of the first social network.
7. The method of claim 6, wherein the first beacon includes an information element (IE) containing discovery information for the first social network.
8. The method of claim 7, wherein the discovery information includes a discovery window of the first social network, services of the first social network, or an identifier for a device in the first social network.
9. A wireless communication station (STA) comprising:
physical layer (PHY) circuitry to receive a first beacon transmitted on a social channel by a device in a first social network; and
one or more processors to
synchronize to the first social network based on time synchronization information in the first beacon, and
extract, from the first beacon,
time stamp information for a synchronization point of the first social network, and
an information element (IE) with discovery information of the first social network; and
a medium access control (MAC) layer to configure the first beacon for transmission to a second social network such that the first beacon includes at least the time synchronization information in the first beacon, a portion of a coverage area of the second social network being outside a coverage area of the first social network, wherein the one or more processors are further configured to:
extract discovery information from a second beacon transmitted from the second social network to determine a discovery window of the second social network, the discovery information being included in the second beacon as an information element (IE); and
discover devices of the second social network, subsequent to transmitting time synchronization information of the first beacon, using the discovery information included in the IE extracted from the second beacon; and wherein
the MAC layer is further configured to communicate with discovered devices of the second social network using the discovery information of the second beacon.
10. The STA of claim 9, wherein
the MAC layer is further arranged to configure the first beacon for transmission during the discovery window of the second social network.
11. The STA of claim 10, wherein the one or more processors are further arranged to:
synchronize to the second social network, using the time synchronization information of the second beacon, responsive to determining that channel conditions in the first social network have deteriorated below a threshold.
12. The STA of claim 10, wherein the MAC is further arranged to:
configure the time synchronization information of the second beacon for transmission to devices in the first social network.
13. The STA of claim 9, wherein the social channel is a Wi-Fi Peer-to-Peer (P2P) channel.
14. A system comprising:
an antenna arranged to receive a first beacon transmitted on a social channel in a first social network;
a memory to store
a list of social channels, the social channels being Wi-Fi Peer-to-Peer (P2P) channels, and
information extracted from the first beacon; and
a processor arranged to
synchronize to the first social network based on time synchronization information in the first beacon,
extract information from the first beacon, the information including time stamp information for a synchronization point for the first social network and discovery information for the first social network, the discovery information being included in the first beacon as an information element (IE)
configure a message, including information extracted from the first beacon, for transmission to a second social network, a portion of a coverage area of the second social network being outside a coverage area of the first social network,
extract discovery information from a second beacon transmitted from the second social network to determine a discovery window of the second social network, the discovery information being included in the second beacon as an IE,
discover devices of the second social network, subsequent to transmitting time synchronization information of the first beacon, using the discovery information included in the IE extracted from the second beacon, and
communicate with discovered devices of the second social network using the discovery information of the second beacon.
15. The system of claim 14, wherein the processor is further arranged to
transmit time synchronization information of the first beacon during the discovery window of the second social network.
16. A non-transitory computer-readable medium comprising instructions that, when executed on a user station (STA) cause the STA to:
receive a first beacon, over a Wi-Fi Peer-to-Peer (P2P) social channel, from a device in a first social network;
synchronize to the first social network based on time synchronization information in the first beacon; and
transmit the time synchronization information of the first beacon to a second social network, a portion of a coverage area of the second social network being outside a coverage area of the first social network,
extract discovery information from a second beacon transmitted from the second social network to determine a discovery window of the second social network, the discovery information being included in the second beacon as an IE,
discover devices of the second social network, subsequent to transmitting time synchronization information of the first beacon, using the discovery information included in the IE extracted from the second beacon, and
communicate with discovered devices of the second social network using the discovery information of the second beacon.
17. The computer-readable medium of claim 16, wherein the instructions further cause the STA to:
transmit the time synchronization information of the first beacon during the discovery window of the second social network; and
transmit time synchronization information of the second beacon to devices in the first social network.
18. The computer-readable medium of claim 17, wherein the instructions further cause the STA to:
synchronize to the second social network, using the time synchronization information of the second beacon, responsive to determining that channel conditions in the first social network have deteriorated below a threshold.