HEWLETT-PACKARD CNT Memory Data Storage

Data storage device including nanotube electron sources
HEWLETT-PACKARD
Priority date July 6, 2001

United States Patent Application 20030007443
Kind Code A1
Nickel, Janice H. January 9, 2003

Matured to USP 6,928,042
What is claimed is:
1. A data storage device comprising an array of nanotubes as electron sources; and a phase-change storage layer proximate tips of the electron sources.

And USP 7,295,503

What is claimed is:

1. A data storage device comprising an array of nanotubes as electron sources.

2. The device of claim 1, wherein the nanotubes are carbon-based.

3. The device of claim 1, wherein the nanotubes are boron nitride-based.

4. The device of claim 1, further comprising a phase-change storage layer proximate tips of the electron sources.

5. The device of claim 1, wherein each nanotube electron source is elongated.

6. The device of claim 5, wherein the nanotubes have an aspect ratio greater than 10:1.

7. The device of claim 1, further comprising word and bit lines for addressing the nanotubes.

8. The device of claim 1, further comprising a micromover for positioning the array.

9. A data storage device comprising: an array of carbon-based nanotubes; and a phase-change storage layer proximate tips of the nanotubes.

10. A data storage device comprising: an array of boron nitride-based nanotubes; and a phase-change storage layer proximate tips of the nanotubes.

11. An electron beam source for a data storage device, the source comprising an array of nanotubes.

12. The electron beam source of claim 11, wherein the nanotubes are carbon nanotubes.

13. The electron beam source of claim 11, wherein the nanotubes are boron nitride nanotubes.

14. The source of claim 11, wherein the nanotubes have an aspect ratio greater than 10:1.

15. The source of claim 11, further comprising word and bit lines for addressing the nanotubes.

16. The device of claim 11, further comprising a micromover for positioning the array.
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Description

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BACKGROUND

[0001] The present invention relates generally to electron sources. The present invention also relates to data storage devices.

[0002] For decades researchers have been working to increase storage density and reduce storage cost of data storage devices such as magnetic hard-drives, optical drives, and semiconductor random access memory. However, increasing the storage density is becoming increasingly difficult because conventional technologies appear to be approaching fundamental limits on storage density. For instance, information storage based on conventional magnetic recording is rapidly approaching fundamental physical limits such as the superparamagnetic limit, below which magnetic bits are not stable at room temperature.

[0003] Storage devices that do not face these fundamental limits are being researched. An example of such an information storage device is described in Gibson et al. U.S. Pat. No. 5,557,596. The device includes multiple electron sources having electron emission surfaces that are proximate a storage medium. During write operations, the electron sources bombard the storage medium with relatively high intensity electron beams. During read operations, the electron sources bombard the storage medium with relatively low intensity electron beams.

[0004] Size of storage bits in such a device may be reduced by decreasing the electron beam diameter. Reducing the storage bit size increases storage density and capacity, and it decreases storage cost.

[0005] "Spindt" emitters could be used for generating focused electron beams in such a device. A Spindt emitter has a conical shape and emits an electron beam at the tip of its cone. The cone tip is made as sharp as possible to reduce operating voltage and achieve a small electron beam diameter.

[0006] However, certain problems arise with Spindt emitters. One problem is that the Spindt emitters are sensitive to impact. The tips of the Spindt emitters are only a few nanometers from the storage medium. If a tip makes contact with the storage medium, it could be damaged. Another problem is directionality of the electron beams emitted from the Spindt emitters. Sometimes an electron beam can come off the side of the cone rather than the tip. Yet another problem is a loss of material from the tips due to energy being greater than the workfunction. The loss of material reduces the effectiveness of the tips.

SUMMARY

[0007] According to one aspect of the present invention, a data storage device includes nanotubes as electron sources. Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention.

LINK

This filing looks like the dominant one - earliest priority date - July 6, 2001.

These are all noted here:
http://www.geocities.com/mr_module/NanoDataRecorders.html?1094841052781