Method of forming controllably conductive oxide

Abstract

In fabricating a memory device, a first electrode is provided. An oxide layer is provided on the first electrode. A second electrode is provided on the oxide layer. In a further method of fabricating a memory device, a first electrode is provided. An oxide layer is provided on the first electrode, the oxide layer comprising an oxygen deficiency and/or defects therein. A second electrode is then provided on the oxide layer.

Claims

1. A system comprising: a processor; and a memory coupled with the processor, the memory comprising at least one memory device, wherein the at least one memory device comprises, a first electrode, an oxide layer, wherein the oxide layer is disposed on and in contact with the first electrode and comprises an oxygen deficiency, and a second electrode, wherein the second electrode is disposed over the oxide layer and comprises titanium.

2. The system of claim 1, wherein the first electrode comprises copper.

3. The system of claim 1, wherein the at least one memory device further comprises a protective layer disposed over the oxide, and wherein the second electrode is disposed over the protective layer.

4. The system of claim 1, wherein the system further comprises a keyboard.

5. The system of claim 1, wherein the system is a hand-held device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as said preferred mode of use, and further objects and advantages thereof, will best be understood by reference to the following detailed description of a illustrative embodiments when read in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a cross-sectional view of an above-described memory device;

(3) FIG. 2 is a plot of current vs. voltage illustrating operating characteristics of the memory device of FIG. 1;

(4) FIGS. 3-8 illustrate various embodiments of the present invention; and

(5) FIGS. 9-11 are systems incorporating memory devices of the present type.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

(6) Reference is now made in detail to specific embodiments of the present invention which illustrate the best mode presently contemplated by the inventor for practicing the invention.

(7) FIGS. 3-5 illustrate a first method for fabricating a metal-insulator-metal (MIM) resistive memory device of the type generally described above. With reference to FIG. 3, initially, an electrode 50 (for example copper) is provided. Next, an alloy 52 of selected metals is deposited on the electrode 50. In this specific embodiment, the alloy 52 includes tantalum and titanium in a mixture thereof. An oxidation step (for example thermal oxidation, plasma-assisted oxidation, or UVlight assisted oxidation) is undertaken to fully oxidize the alloy to form an oxide layer 54 (which is a mixture of titanium oxide and tantalum oxide, i.e., TiO.sub.2 and Ta.sub.2O.sub.5) on and in contact with the electrode 50 (FIG. 4). Then, a second electrode 56 (for example titanium) is provided on and in contact with the oxide layer 54 to form the metal-insulator-metal (MIM) memory device 58 (FIG. 5).

(8) The content of the oxide layer depends 54 on the particular metals and proportions thereof making up the alloy 52. In this particular case, the oxide layer 54 made up of the mixture of TiO.sub.2 and Ta.sub.2O.sub.5 has operational characteristics which are different from that of the Ta.sub.2O.sub.5 layer 34 of the previously described device. Indeed, the operational characteristics of the overall memory device 58 will depend on the particular metals and proportions thereof making up the alloy 54. Thus, the operational characteristics of the fabricated memory device 58, i.e., for example, program and erase voltages, on-resistance characteristics, and device stability may be based on the selected content of the alloy 54 as required.

(9) FIGS. 6-8 illustrate various other embodiments of the invention. Initially (FIG. 6), an electrode 60 (for example copper) is provided. Next, an oxide 62 (in this particular embodiment Ta.sub.2O.sub.5) is provided on and in contact with the electrode 60 by any suitable means. A thin metal protective layer 64, for example, aluminum, may then be deposited on and in contact with the oxide 62. Next (FIG. 7), an implantation step for implanting material through the layer 64 and into the oxide 62 is undertaken. This implantation step may take a number of forms. For example, the implanted material may be titanium, nitrogen, or silicon. Each of these materials when so implanted in the Ta.sub.2O.sub.5 will pull oxygen away from the tantalum in the oxide 62 to create a layer 66 comprising oxide and the implanted material which has an overall oxygen deficiency, thereby decreasing resistance thereof as compared to a Ta.sub.2O.sub.5 layer. The implanted material may further for example be tantalum, which also will create a layer 66 comprising oxide and the implanted material having an overall oxygen deficiency by providing an excess of metal atoms for the oxygen present in the layer. The protective layer 64 is included in order to seal out atmospheric oxygen in order to retain the oxygen-deficient state of the layer 66. Then, a second electrode 68 (for example titanium) is provided on and in contact with the protective layer 64 to form the metal-insulator-metal (MIM) memory device 70 (FIG. 8).

(10) The implantation step also causes damage to the oxide 62, causing defects in the layer 66 comprising oxide and the implanted material so as to increase the conductivity thereof. Indeed, materials for implantation may be selected to cause damage to the oxide 62 without causing an oxygen deficiency therein (for example inert implant materials such as argon, krypton or xenon). Indeed, oxygen itself may be implanted for this purpose.

(11) The operational characteristics of the fabricated memory device 70, i.e., for example, program and erase voltages, on-resistance characteristics, and device stability and may be based on the content of the implanted material as required.

(12) FIG. 9 illustrates a system 200 utilizing memory devices as described above. As shown therein, the system 200 includes hand-held devices 202 in the form of cell phones, which communicate through an intermediate apparatus such as a tower 204 (shown) and/or a satellite. Signals are provided from one cell phone to the other through the tower 204. Such a cell phone with advantage uses memory devices of the type described above for data storage, for example names, telephone number and other data. One skilled in the art will readily understand the advantage of using such memory devices in other hand-held devices 202 which utilize data storage, such as portable media players, personal digital assistants, digital cameras and the like.

(13) FIG. 10 illustrates another system 300 utilizing memory devices as described above. The system 300 includes a vehicle 302 having an engine 304 controlled by an electronic control unit 306. The electronic control unit 306 with advantage uses memory devices of the type described above for data storage, or example data relating to engine and vehicle operating conditions.

(14) FIG. 11 illustrates yet another system 400 utilizing memory devices as described above. This system 400 is a computer 402 which includes an input in the form of a keyboard, and a microprocessor for receiving signals from the keyboard through an interface. The microprocessor also communicates with a CDROM drive, a hard drive, and a floppy drive through interfaces. Output from the microprocessor is provided to a monitor through an interface. Also connected to and communicating with the microprocessor is memory which may take the form of ROM, RAM, flash and/or other forms of memory. The memory with advantage uses memory devices of the type described above for storage of any data which is of use.

(15) The foregoing description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Other modifications or variations are possible in light of the above teachings.

(16) The embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill of the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.