What is claimed is:
1. A twin bit cell flash memory device, the device comprising:
a semiconductor substrate;
a source and a drain positioned in a predetermined area of the semiconductor substrate, and the drain and the source separated by a predetermined distance;
a channel positioned on the surface of the semiconductor substrate between the source and the drain;
a first dielectric layer covering the surface of the channel;
a polysilicon germanium layer covering the surface of the first dielectric layer, the polysilicon germanium layer having an insulating region for separating the polysilicon germanium layer and forming two isolated conductive regions so as to form a twin bit cell structure;
a second dielectric layer covering the surface of the polysilicon germanium layer; and
a gate covering the surface of the second dielectric layer;
wherein each conductive region serves as a charge trapping layer so as to receive and store electrons injected into the conductive region to generate a respective bit.
2. The flash memory device of claim 1 wherein the semiconductor substrate is a P-type substrate, and the source and the drain are both N-type doped areas.
3. The flash memory device of claim 1 wherein the semiconductor substrate is an N-type substrate, and the source and the drain are both P-type doped areas.
4. The flash memory device of claim 1 wherein the chemical composition of the polysilicon germanium layer is Si1xGexx0.051.0.
5. The flash memory device of claim 1 wherein the insulating region is formed by implanting a high concentration of oxygen dopant into the polysilicon germanium layer, and then performing a thermal process.
6. The flash memory device of claim 5 wherein the high concentration of oxygen dopant is formed by an oxygen ion implantation process, the implanting dosage being approximately 121018cm2, the implanting energy ranging from 20 KeV to 80 KeV.
7. The flash memory device of claim 5 wherein the thermal process is a high temperature annealing process with a temperature range of 950 C. to 1150 C.
8. The flash memory device of claim 1 wherein the insulating region is formed by implanting a high concentration of nitrogen dopant into the polysilicon germanium layer, and then performing a thermal process.
9. The flash memory device of claim 1 wherein an oxide layer is also formed on the exposed side walls of each conductive region.
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 planting container suitable to be three-dimensionally stacked to form a plurality of planting columns by using a plurality of ones with the same structure, the planting columns being arranged around a center line parallel to the gravity direction so as to set up a planting tower, the planting container comprising:
a bottom wall; and
a side wall extending from the peripheral of the bottom wall and defining a containing space with the bottom wall, and the side wall having a planting opening communicating with the containing space,
wherein the side wall has a top end and a bottom end, the bottom end is closer to the bottom wall than the top end, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the bottom end of the upper planting container engages with the top end of the lower planting container,
wherein the side wall laterally tilts towards the center line relatively to the bottom wall, so that the planting column tilts towards the adjacent planting column and tilts towards the center line.
2. The planting container as claimed in claim 1, wherein the bottom wall has a plurality of drain holes.
3. The planting container as claimed in claim 1, wherein the bottom end has a step structure, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the upper planting container engages with the lower planting container through the step structure.
4. The planting container as claimed in claim 1, wherein the planting opening extends to the top end, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the side wall of the upper planting container is overlapped with the planting opening of the lower planting container for defining the region of the planting opening communicating with the containing space.
5. The planting container as claimed in claim 1, further comprising:
a holding cup connected to the side wall and communicating with the planting opening.
6. The planting container as claimed in claim 1, wherein the side wall has a front portion, a first side portion, a second side portion and a rear portion, the front portion is opposite to the rear portion, the first side portion connects a side of the front portion and a side of the rear portion, the second side portion connects another side of the front portion and another side of the rear portion, both the first side portion and the second side portion tilt relatively to the bottom wall along the direction from the first side portion to the second side portion so that the planting column tilts towards the adjacent planting column, and both the front portion and the rear portion tilt relatively to the bottom wall along the direction from the front portion to the rear portion so that the planting columns tilt towards the center line.
7. The planting container as claimed in claim 6, wherein the side wall has a first guiding pipe notch and a second guiding pipe notch suitable for allowing a guiding pipe to extend and pass through, the first guiding pipe notch is located at the first side portion and extends to the top end, the second guiding pipe notch is located at the second side portion and extends to the top end, the lower end of the first guiding pipe notch is closer to the bottom wall than the lower end of the second guiding pipe notch, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the side wall of the upper planting container is overlapped with the first guiding pipe notch and the second guiding pipe notch of the lower planting container for defining the region used to allow the guiding pipe extending and passing through by the first guiding pipe notch and the second guiding pipe notch.
8. The planting container as claimed in claim 7, wherein the depth of the first guiding pipe notch relative to the top end is greater than the depth of the second guiding pipe notch relative to the top end.
9. A planting tower, comprising:
a plurality of planting columns arranged around a center line parallel to the gravity direction, each of the planting columns comprising a plurality of planting containers three-dimensionally stacked by each other with the same structure,
wherein each of the planting containers comprises:
a bottom wall; and
a side wall extending from the peripheral of the bottom wall and defining a containing space with the bottom wall, the side wall having a planting opening communicating with the containing space,
wherein the side wall has a top end and a bottom end, the bottom end is closer to the bottom wall than the top end, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the bottom end of the upper planting container engages with the top end of the lower planting container,
wherein the side wall laterally tilts towards the center line relatively to the bottom wall, so that the planting column tilts towards the adjacent planting column and tilts towards the center line.
10. The planting tower as claimed in claim 9, wherein the bottom wall has a plurality of drain holes.
11. The planting tower as claimed in claim 9, wherein the bottom end has a step structure, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the upper planting container engages with the lower planting container through the step structure.
12. The planting tower as claimed in claim 9, wherein the planting opening extends to the top end, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the side wall of the upper planting container is overlapped with the planting opening of the lower planting container for defining the region of the planting opening communicating with the containing space.
13. The planting tower as claimed in claim 9, wherein the planting container further comprises:
a holding cup connected to the side wall and communicating with the planting opening.
14. The planting tower as claimed in claim 9, wherein the side wall has a front portion, a first side portion, a second side portion and a rear portion, the front portion is opposite to the rear portion, the first side portion connects a side of the front portion and a side of the rear portion, the second side portion connects another side of the front portion and another side of the rear portion, both the first side portion and the second side portion tilt relatively to the bottom wall along the direction from the first side portion to the second side portion so that the planting column tilts towards the adjacent planting column, and both the front portion and the rear portion tilt relatively to the bottom wall along the direction from the front portion to the rear portion so that the planting columns tilt towards the center line.
15. The planting tower as claimed in claim 9, further comprising:
a guiding pipe extending and passing through the planting containers for applying planting liquid material,
wherein the side wall has a first guiding pipe notch and a second guiding pipe notch for allowing the guiding pipe to extend and pass through, the first guiding pipe notch is located at the first side portion and extends to the top end, the second guiding pipe notch is located at the second side portion and extends to the top end, the lower end of the first guiding pipe notch is closer to the bottom wall than the lower end of the second guiding pipe notch, and when two of the planting containers with the same structure are three-dimensionally stacked by each other, the side wall of the upper planting container is overlapped with the first guiding pipe notch and the second guiding pipe notch of the lower planting container for defining the region used to allow the guiding pipe extending and passing through by the first guiding pipe notch and the second guiding pipe notch.
16. The planting tower as claimed in claim 15, wherein the depth of the first guiding pipe notch relative to the top end is greater than the depth of the second guiding pipe notch relative to the top end so that a section of the guiding pipe passing through the same planting container tilts towards the gravity direction.
17. The planting tower as claimed in claim 9, further comprising:
a base for setting up the planting columns.
18. The planting tower as claimed in claim 9, further comprising:
a guiding pipe extending and passing through the planting containers for applying planting liquid material.
19. The planting tower as claimed in claim 18, wherein the guiding pipe helically extends and passes through the planting containers.
20. The planting tower as claimed in claim 9, wherein the planting column further comprises:
a bottom frame connected to the bottom of the corresponding planting container for increasing the height of the corresponding planting column.