1. A split gate type nonvolatile semiconductor memory device, the device comprising:
a semiconductor substrate which has a plurality of source regions in a word line direction;
a plurality of floating gate pairs formed to interpose a gate insulating layer therebetween on the semiconductor substrate, and which share the source region with an adjacent memory cell while facing with one another;
inter-gate insulating layers which are formed on surfaces of the floating gate pair;
tunneling insulating layers which are formed along an opposite facing sidewall of the floating gate; and
a plurality of control gate pairs which have a protrusion vertically extending at a position by a predetermined distance from the sidewall of the floating gate while being in contact with surfaces of the tunneling insulating layers, and which extends to have a cover part encompassing the floating gate between the protrusion and a sidewall and an upper surface of the floating gate.
2. The device of claim 1, wherein the control gate entirely overlaps the floating gate.
3. The device of claim 1, wherein the control gate partially overlaps the floating gate.
4. The device of claim 1, wherein the tunneling insulating layer vertically extends by a predetermined distance from a sidewall portion of the protrusion of the control gate.
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. An electrophotographic photoreceptor, comprising:
an electroconductive substrate; and
a photosensitive layer located overlying the electroconductive substrate,
wherein the photosensitive layer comprises units obtained from a radical polymerizing monomer at a surface thereof, wherein the radical polymerizing monomer comprises an aliphatic group having two radical polymerizing groups and a charge transporting group including no radical polymerizing group, connected to each other by a single bond.
2. The electrophotographic photoreceptor of claim 1, wherein the photosensitive layer further comprises units obtained from a radical polymerizing monomer having three or more radical polymerizing groups within a molecule.
3. The electrophotographic photoreceptor of claim 2, wherein the photosensitive layer further comprises a photo polymerization initiator.
4. The electrophotographic photoreceptor of claim 1, wherein each of the radical polymerizing groups is a member selected from the group consisting of acryloyloxy groups and methacryloyloxy groups.
5. The electrophotographic photoreceptor of claim 1, wherein the aliphatic group having two radical polymerizing groups has the following formula (1):
wherein Ra and Rb each, independently, represent a hydrogen atom or a methyl group.
6. The electrophotographic photoreceptor of claim 1, wherein the radical polymerizing monomer has the following formula (2):
wherein Ra and Rb each, independently, represent a hydrogen atom or a methyl group; Rc and Rd each, independently, represent an alkyl group having 1 to 6 carbon atoms and optionally having a substituent, an alkoxy group optionally having a substituent or an aryl group optionally having a substituent, or Rc and Rd are combined with each other to form a cyclic hydrocarbon ring having 5 to 8 carbon atoms; Ar1 and Ar2 each, independently, represent an aryl group optionally having a substituent; and i and j each, independently, represent 0 or an integer of from 1 to 4.
7. The electrophotographic photoreceptor of claim 1, wherein the radical polymerizing monomer has the following formula (3):
wherein Ra and Rb each, independently, represent a hydrogen atom or a methyl group; Rc, Rd, Re and Rf each, independently, represent an alkyl group having 1 to 6 carbon atoms and optionally has a substituent, an alkoxy group optionally having a substituent or an aryl group optionally having a substituent, or Rc and Rd are combined with each other to form a cyclic hydrocarbon ring having 5 to 8 carbon atoms; Ar1 and Ar2 each, independently, represent an aryl group optionally having a substituent; i and j each, independently, represent 0 or an integer of from 1 to 4; and k and l each, independently, represent 0 or an integer of from 1 to 5.
8. The electrophotographic photoreceptor of claim 1, wherein the radical polymerizing monomer has the following formula (4):
wherein Ra and Rb each, independently, represent a hydrogen atom or a methyl group; Rc and Rd each, independently, represent an alkyl group having 1 to 6 carbon atoms optionally having a substituent, an alkoxy group optionally having a substituent or an aryl group optionally having a substituent, or Rc and Rd are combined with each other to form a cyclic hydrocarbon ring having 5 to 8 carbon atoms; Ar1 and Ar2 each, independently, represent an aryl group optionally having a substituent; and i and j each, independently, represent 0 or an integer of from 1 to 4.
9. The electrophotographic photoreceptor of claim 1, wherein the radical polymerizing monomer has the following formula (5):
wherein Ra and Rb each, independently, represent a hydrogen atom or a methyl group; Rc, Rd, Re and Rf each, independently, represent an alkyl group having 1 to 6 carbon atoms optionally having a substituent, an alkoxy group optionally having a substituent or an aryl group optionally having a substituent; Ar1 and Ar2 each, independently, represent an aryl group optionally having a substituent; i and j each, independently, represent 0 or an integer of from 1 to 4; and k and l each, independently, represent 0 or an integer of from 1 to 5.
10. The electrophotographic photoreceptor of claim 1, wherein the photosensitive layer further comprises:
a charge generation layer, located overlying the electroconductive substrate;
a charge transport layer, located overlying the charge generation layer; and
a crosslinked charge transport layer, located overlying the charge transport layer;
wherein the crosslinked charge transport layer comprises units obtained from a radical polymerizing monomer, wherein the radical polymerizing monomer comprises an aliphatic group having two radical polymerizing groups and a charge transporting group including no radical polymerizing group, connected to each other by a single bond.
11. The electrophotographic photoreceptor of claim 10, wherein the crosslinked charge transport layer further comprises units obtained from a radical polymerizing monomer having three or more radical polymerizing groups within a molecule.
12. The electrophotographic photoreceptor of claim 11, wherein the crosslinked charge transport layer further comprises a photo polymerization initiator.
13. The electrophotographic photoreceptor of claim 10, wherein the crosslinked charge transport layer has a thickness of from 1 to 10 \u03bcm.
14. The electrophotographic photoreceptor of claim 10, wherein the crosslinked charge transport layer is insoluble in an organic solvent.
15. The electrophotographic photoreceptor of claim 11, wherein a ratio of a molecular weight of the units obtained from a radical polymerizing monomer having three or more radical polymerizing groups within a molecule to the number of radical polymerizing functional groups is not greater than 250.
16. An image forming method, comprising:
charging the electrophotographic photoreceptor according to claim 1;
irradiating the electrophotographic photoreceptor to form an electrostatic latent image thereon;
developing the electrostatic latent image with a toner to form a toner image thereon; and
transferring the toner image onto a receiving material.
17. An image forming apparatus, comprising:
the electrophotographic photoreceptor according to claim 1;
a charger configured to charge the electrophotographic photoreceptor;
an irradiator configured to irradiate the electrophotographic photoreceptor to form an electrostatic latent image thereon;
an image developer configured to develop the electrostatic latent image with a toner to form a toner image thereon; and
a transferer configured to transfer the toner image onto a receiving material.
18. A process cartridge detachable from an image forming apparatus, comprising:
the electrophotographic photoreceptor according to claim 1; and
at least one member selected from the group consisting of a charger, an image developer, a transferer, a cleaner and a discharger.