TUNNELING BARRIER RESISTOR AND METHODS FOR FORMING THE SAME
A tunneling barrier resistor includes a first electrode layer containing a first nonmagnetic iron-group-containing alloy layer which includes a first refractory metal, a second electrode layer containing a second nonmagnetic iron-group-containing alloy layer which includes a second refractory metal, and a first tunneling barrier dielectric layer located between the first electrode layer and the second electrode layer.
1 . A device comprising a tunneling barrier resistor, wherein the tunneling barrier resistor comprises:
a first electrode layer comprising a first nonmagnetic iron-group-containing alloy layer which includes a first refractory metal;
a second electrode layer comprising a second nonmagnetic iron-group-containing alloy layer which includes a second refractory metal; and
a first tunneling barrier dielectric layer located between the first electrode layer and the second electrode layer.
2 . The device of claim 1 , wherein:
the first electrode comprises a first mixed metallic electrode layer comprising a first nonmagnetic iron-group-containing alloy and the first refractory metal; and
the second electrode comprises a second mixed metallic electrode layer comprising a second nonmagnetic iron-group-containing alloy and the second refractory metal.
3 . The device of claim 2 , wherein:
the first electrode is formed by depositing the first nonmagnetic iron-group-containing alloy layer having a thickness of 1 nm or less and a first refractory metal layer having a thickness of 1 nm or less in contact with each other; and
the second electrode is formed by depositing the second nonmagnetic iron-group-containing alloy layer having a thickness of 1 nm or less and a second refractory metal layer having a thickness of 1 nm or less in contact with each other.
4 . The device of claim 3 , wherein:
the first nonmagnetic iron-group-containing alloy layer is deposited as an amorphous layer;
the second nonmagnetic iron-group-containing alloy layer is deposited as an amorphous layer;
the first electrode layer comprises the mixed metallic electrode layer of a CoFe or CoFeB alloy, and the first refractory metal comprising Ta, W, Cr, Mo or Hf; and
the second electrode layer comprises the mixed metallic electrode layer of a CoFe or CoFeB alloy, and the second refractory metal comprising Ta, W, Cr, Mo or Hf.
5 . The device of claim 4 , wherein:
the first electrode layer comprises the mixed metallic electrode layer of the tungsten and the CoFeB alloy; and
the second electrode layer comprises the mixed metallic electrode layer of the tungsten and the CoFeB alloy.
6 . The device of claim 4 , wherein:
the first tunneling barrier dielectric layer thickness ranges from 0.5 nm to 1.5 nm;
the first nonmagnetic iron-group-containing alloy layer is deposited with a thickness in a range from 0.3 nm to 1 nm;
the first refractory metal layer is deposited with a thickness in a range from 0.2 nm to 1 nm that is less than the thickness of the first nonmagnetic iron-group-containing alloy layer;
the first electrode layer thickness ranges from 0.5 nm to 1.5 nm;
the second nonmagnetic iron-group-containing alloy layer is deposited with a thickness in a range from 0.3 nm to 1 nm;
the second refractory metal layer is deposited with a thickness in a range from 0.2 nm to 1 nm that is less than the thickness of the second nonmagnetic iron-group-containing alloy layer; and
the second electrode layer thickness ranges from 0.5 nm to 1.5 nm.
7 . The device of claim 1 , further comprising:
a third electrode layer comprising a third nonmagnetic iron-group-containing alloy layer which includes a refractory metal; and
a second tunneling barrier dielectric layer located between the third electrode layer and the second electrode layer.
8 . The device of claim 1 , further comprising a non-Ohmic device component that is electrically connected in series with the tunneling barrier resistor.
9 . The device of claim 8 , wherein the non-Ohmic device component comprises a negative differential resistance element.
10 . The device of claim 9 , wherein the negative differential resistance element comprises a spin torque oscillator (STO), an impact ionization avalanche transit-time (IMPATT) diode, or a Gunn diode.
11 . The device of claim 9 , further comprising a capacitor electrically connected in parallel with the series connection of the tunneling barrier resistor and the negative differential resistance element to a power source.
12 . The device of claim 8 , wherein the non-Ohmic device component comprises an ovonic threshold switch (OTS) offset voltage memory cell.
13 . The device of claim 8 , wherein the non-Ohmic device component comprises an ovonic threshold switch (OTS) selector of a magnetoresistive random access memory cell.
14 . The device of claim 8 , wherein the non-Ohmic device component comprises a resistive random access memory (ReRAM) cell.
15 . A method of operating the device of claim 1 , comprising passing a current through the tunneling barrier resistor using quantum tunneling.
16 . A method of forming a tunneling barrier resistor, comprising:
depositing a first refractory metal layer;
depositing a first amorphous iron-group-containing alloy layer on the first refractory metal layer to form a first electrode layer comprising a first nonmagnetic iron-group-containing alloy layer which includes the first refractory metal;
depositing a first tunneling barrier dielectric layer on the first electrode layer;
depositing a second amorphous iron-group-containing alloy layer on the first tunneling barrier dielectric layer; and
depositing a second refractory metal layer on the second amorphous iron-group-containing alloy layer to form a second electrode layer comprising a second nonmagnetic iron-group-containing alloy layer which includes the second refractory metal.
17 . The method of claim 16 , wherein:
the first electrode comprises a first mixed metallic electrode layer comprising a first nonmagnetic iron-group-containing alloy and the refractory metal; and
the second electrode comprises a second mixed metallic electrode layer comprising a second nonmagnetic iron-group-containing alloy and the refractory metal.
18 . The method of claim 17 , wherein:
the first electrode layer comprises the mixed metallic electrode layer of a CoFe or CoFeB alloy, and the first refractory metal comprising Ta, W, Cr, Mo or Hf; and
the second electrode layer comprises the mixed metallic electrode layer of a CoFe or CoFeB alloy, and the second refractory metal comprising Ta, W, Cr, Mo or Hf.
19 . The method of claim 18 , wherein:
the first electrode layer comprises the mixed metallic electrode layer of the tungsten and the CoFeB alloy;
the second electrode layer comprises the mixed metallic electrode layer of the tungsten and the CoFeB alloy;
the first tunneling barrier dielectric layer thickness ranges from 0.5 nm to 1.5 nm;
the first nonmagnetic iron-group-containing alloy layer is deposited with a thickness in a range from 0.3 nm to 1 nm;
the first refractory metal layer is deposited with a thickness in a range from 0.2 nm to 1 nm, which is less than the thickness of the first nonmagnetic iron-group-containing alloy layer;
the first electrode layer thickness ranges from 0.5 nm to 1.5 nm;
the second nonmagnetic iron-group-containing alloy layer is deposited with a thickness in a range from 0.3 nm to 1 nm;
the second refractory metal layer is deposited with a thickness in a range from 0.2 nm to 1 nm, which is less than the thickness of the second nonmagnetic iron-group-containing alloy layer; and
the second electrode layer thickness ranges from 0.5 nm to 1.5 nm.
20 . The method of claim 16 , further comprising forming a negative differential resistance element in series with the tunneling barrier resistor.