Small, scalable resistive element and method of manufacturing
An improved scalable, resistive element for use in a semiconductor device that can be produced with a small feature size and precise resistance is provided by the present invention. The resistive element includes a base layer positioned on top of a metal line. A seed layer of is deposited on top of the base layer. A thin barrier layer of Al is deposited on top of the seed layer and oxidized. A non-magnetic metal layer is then deposited on top of the barrier layer. The base layer and the non-magnetic metal layer form electrodes on either side of the barrier layer. The barrier layer is thin enough that a tunneling current can travel between the electrodes. The resulting resistive element may be constructed with a high resistance and a very small feature size.
1 . A method for producing a resistive element comprising the steps of:
depositing a seed layer over a first electrode; and
depositing an insulating barrier layer over the seed layer wherein the barrier layer is thin enough to allow a tunneling current to flow to a second electrode;
wherein the resistive element comprises a resistance that is a function of the thickness of the insulating barrier layer.
2 . The method of claim 1 further comprising the step of depositing a smoothing layer of Ta over said first electrode prior to depositing said seed layer.
3 . The method of claim 1 further comprising the step of oxidizing the insulating barrier layer.
4 . The method of claim 1 further comprising the step of patterning the resistive element such that the resistive element has a predetermined resistance value.
5 . The method of claim 1 wherein the step of depositing a seed layer over a first electrode further comprises depositing a seed layer of CoFe.
6 . A method of producing a resistor for use in a semiconductor device, said method comprising:
depositing a base layer over a metal contact point;
depositing a seed layer over the base layer;
depositing a barrier layer over the seed layer; and
depositing a non-magnetic metal layer over the barrier layer.
7 . The method of claim 6 further comprising the step of depositing a protective cap layer over the non-magnetic metal layer.
8 . The method of claim 6 further comprising the step of patterning the resistor such that the resistor has a desired resistance value.
9 . The method of claim 6 further comprising the step of oxidizing the barrier layer.
10 . The method of claim 9 wherein the barrier layer is oxidized with an oxygen plasma.
11 . The method of claim 6 wherein the step of depositing a seed layer over of the base layer comprises depositing a seed layer of CoFe over the base layer.
12 . The method of claim 6 wherein the step of depositing a base layer over a metal contact point comprises depositing a base layer containing Ta over a metal contact point.
13 . The method of claim 6 wherein the step of depositing a barrier layer over the seed layer comprises depositing a barrier layer of Al over the seed layer.
14 . The method of claim 6 wherein the step of depositing a non-magnetic metal layer over the barrier layer comprises depositing a layer of Al over the barrier layer.
15 . The method of claim 6 wherein the step of depositing a barrier layer over the seed layer comprises depositing a barrier layer less than approximately 2 nanometers thick over the seed layer.
16 . The method of claim 6 further comprising depositing a smoothing layer of Ta over said base layer.
17 . A resistive element for use in a semiconductor device, said resistive element comprising:
a base layer positioned over a metal contact;
a seed layer positioned over the base layer;
a barrier layer positioned over the seed layer; and
a non-magnetic metal layer positioned over the barrier layer.
18 . The resistive element of claim 17 further comprising a protective cap layer positioned over the non-magnetic metal layer.
19 . The resistive element of claim 17 wherein the barrier layer has been at least partially oxidized.
20 . The resistive element of claim 17 further comprising a smoothing layer of Ta positioned over said base layer.
21 . The resistive element of claim 17 wherein the base layer further comprises TaN.
22 . The resistive element of claim 17 wherein said seed layer further comprises CoFe.
23 . The resistive element of claim 17 wherein said non-magnetic metal layer further comprises Al.
24 . A resistor comprising:
a top electrode formed from one of a magnetic and non-magnetic metal;
a bottom electrode formed of a non-magnetic metal; and
an insulating layer positioned between said bottom electrode and said top electrode wherein said insulating layer is thin enough to allow a tunneling current to be established between said top electrode and said bottom electrode.
25 . The resistor of claim 24 wherein said insulating layer further comprises a thin layer of oxidized Al.
26 . The resistor of claim 24 wherein said insulating layer further comprises a seed layer of CoFe.
27 . The resistor of claim 24 further comprising a smoothing layer of Ta upon which said insulating layer is deposited.
28 . The resistor of claim 24 wherein said bottom electrode comprises TaN.
29 . The resistor of claim 24 wherein said top electrode further comprises at least one of Al and TaN.
30 . The resistor of claim 24 wherein said insulating layer is less than approximately 2 nanometers in thickness.