Thin film structure, semiconductor device including the same, and semiconductor apparatus including semiconductor device
Provided are a thin film structure, a semiconductor device including the thin film structure, and a semiconductor apparatus including the semiconductor device. The thin film structure includes a substrate, and a ferroelectric layer on the substrate. The ferroelectric layer includes a compound having fluorite structure, in which a <001> crystal direction is aligned in a normal direction of a substrate, and having an orthorhombic phase and including fluorine. The ferroelectric layer may have ferroelectricity.
1. A thin film structure comprising:
a substrate; and
a ferroelectric layer on the substrate and comprising a compound having a fluorite structure in which a <001> crystal direction is aligned along a normal direction of the substrate, the ferroelectric layer having an orthorhombic phase and comprising fluorine,
wherein an uppermost atomic layer of the ferroelectric layer includes fluorine.
2. The thin film structure of claim 1 ,
wherein the ferroelectric layer comprises the compound having the fluorite structure where a <001> crystal direction is a dominant ratio in the ferroelectric layer.
3. The thin film structure of claim 1 ,
wherein the ferroelectric layer comprises the compound having the fluorite structure where crystal grains having a <001> crystal direction aligned along a normal direction of the substrate in an amount of about 20 weight % or more in the ferroelectric layer.
4. The thin film structure of claim 1 ,
wherein the ferroelectric layer has ferroelectricity.
5. The thin film structure of claim 1 ,
wherein an amount of the orthorhombic phase in the compound having the fluorite structure is at least about 50%.
6. The thin film structure of claim 1 ,
wherein the ferroelectric layer comprises a compound fluorite structure represented by Formula 1:
MO 2-ε F α X β Formula 1
wherein, in Formula 1, M is Hf, Zr, or a combination of Hf and Zr, X is O, N, H, or a combination of O, N, or H, 0<α≤1 and 0≤β≤1, wherein the sum of α and β is about 1 or less, and 0≤ε≤1.
7. The thin film structure of claim 1 ,
wherein the ferroelectric layer further comprises a dopant material selected from the group including C, Si, Ge, Sn, Pb, Al, Y, La, Gd, Mg, Ca, Sr, Ba, Ti.
8. The thin film structure of claim 7 ,
wherein the ferroelectric layer comprises the compound having the fluorite structure represented by Formula 1, wherein an amount of the dopant material is in a range of greater than 0 atom % (at %) to about 20 at % of an amount of M:
MO 2-ε F α X β Formula 1
wherein, in Formula 1, M is Hf, Zr, or a combination of Hf and Zr, X is O, N, H, or a combination of O, N, or H, 0<α≤1 and 0≤β≤1, wherein the sum of a and B is about 1 or less, and 0≤ε≤1.
9. The thin film structure of claim 1 ,
wherein a thickness of the ferroelectric layer is in a range of about 0.1 nm or more to about 10 nm or less.
10. The thin film structure of claim 1 ,
wherein the ferroelectric layer comprises a first region and a second region,
the first region comprises a first compound having the fluorite structure represented by Formula 1-1, and
the second region comprises a second compound having the fluorite structure represented by Formula 1-2:
MO 2-ζ F γ1 X γ2 Formula 1-1
MO 2-η F δ1 X δ2 Formula 1-2
wherein, in Formulae 1-1 and 1-2, M is Hf, Zr, or a combination of Hf and Zr; X is O, N, H, or a combination of O, N, or H; 0<γ1≤1 and 0≤γ2≤1, wherein the sum of γ1 and γ2 is about 1 or less, and 0≤ζ≤1; 0≤δ1≤1 and 0≤δ2≤1, wherein the sum of δ1 and δ2 is about 1 or less, and 0≤η≤1; And γ1 and δ1 are different from each other.
11. The thin film structure of claim 10 ,
wherein γ1>δ1.
12. The thin film structure of claim 10 ,
wherein δ1 is about 0.1 or less, and γ1 is in a range of about 0.1 or more to about 0.95 or less.
13. The thin film structure of claim 10 ,
wherein at least one of
the second region is between the substrate and the first region,
or the first region is located the substrate and the second region.
14. A semiconductor device comprising the thin film structure of claim 1 ; and
at least one active or passive device.
15. The semiconductor device of claim 14 comprising:
a first electrode; and
a second electrode apart from the first electrode,
wherein the ferroelectric layer is between the first electrode and the second electrode, and
at least one of the first electrode or the second electrode corresponds to the substrate.
16. The semiconductor device of claim 15 , further comprising:
a dielectric layer comprising a paraelectric material.
17. The semiconductor device of claim 16 ,
wherein the dielectric layer is between the ferroelectric layer and the substrate.
18. The semiconductor device of claim 15 ,
wherein one of the first electrode and the second electrode comprises a semiconductor material.
19. The semiconductor device of claim 18 ,
wherein the one of the first electrode and the second electrode comprising a semiconductor material comprises a source and a drain.
20. A semiconductor apparatus comprising the semiconductor device of claim 14 ; and
at least one active or passive device.
21. A transistor comprising:
a substrate;
a source/drain region in the substrate; and
a ferroelectric layer on the substrate and between the source/drain region, the ferroelectric layer comprising a fluorine compound in an orthorhombic phase, the fluorine compound being a compound in which a <001> crystal direction is aligned along a normal direction of the substrate, wherein an uppermost atomic layer of the ferroelectric layer includes fluorine.
22. The transistor of claim 21 , further comprising:
a halo region in the substrate, the halo region having a conductivity type opposite to a conductivity type of the source/drain region.
23. The transistor of claim 22 , wherein a concentration of impurities in the halo region is less than a concentration of impurities in the source/drain region.
24. The transistor of claim 21 , further comprising:
a gate electrode on the ferroelectric layer, wherein
a thickness of the gate electrode is less than a thickness of the ferroelectric layer.
25. The thin film structure of claim 1 , wherein at least one orthorhombic unit cell of the orthorhombic is arranged in the <001> crystal direction with a fluorite structure consisting of one element of a metal and two elements of fluorine.