Ferroelectric memory cells including ferroelectric crystalline materials having polar and chiral crystal structures, and related memory devices

Abstract

A ferroelectric memory device includes a plurality of memory cells. Each of the memory cells comprises at least one electrode and a ferroelectric crystalline material disposed proximate the at least one electrode. The ferroelectric crystalline material is polarizable by an electric field capable of being generated by electrically charging the at least one electrode. The ferroelectric crystalline material comprises a polar and chiral crystal structure without inversion symmetry through an inversion center. The ferroelectric crystalline material does not consist essentially of an oxide of at least one of hafnium (Hf) and zirconium (Zr).

1 . A ferroelectric memory cell, comprising:
 a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center,   wherein the ferroelectric crystalline material comprises a material selected from the group consisting of SnGa 4 Se 7 , SeO 2 , Ti x Ta y La z O 11 , where x+y+z=3, Ti 1.92 Ta 1.08 La 3 O 11 , and In 11 Mo 40 O 62 .   
     
     
         2 . The ferroelectric memory cell of  claim 1 , wherein the ferroelectric crystalline material comprises Ti 1.92 Ta 1.08 La 3 O 11 . 
     
     
         3 . A ferroelectric memory cell, comprising:
 a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center,   wherein the ferroelectric crystalline material comprises a material selected from the group consisting of TiSO 5 , V 2 O 5 , Sr 5 Nb 5 O 16 , and ZrMo 2 O 8 .   
     
     
         4 . A ferroelectric memory cell, comprising:
 a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center,   wherein the ferroelectric crystalline material comprises a material selected from the group consisting of Si 2 Y 2 O 7 , Sr 2 P 2 O 7 , and Ti 0.98 Zr 0.02 RbPO 5 .   
     
     
         5 . A ferroelectric memory cell, comprising:
 a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center,   wherein the ferroelectric crystalline material has a tetragonal crystal structure corresponding to a space group selected from the group consisting of P422, P42 1 2, P4 1 22, P4 1 2 1 2, P4 2 22, P4 2 2 1 2, P4 3 22, and P4 3 2 1 2.   
     
     
         6 . A ferroelectric memory device including memory cells, each memory cell comprising:
 at least one electrode; and   a ferroelectric crystalline material disposed proximate the at least one electrode and polarizable by an electric field responsive to an electrical charge of the at least one electrode, the ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center, the ferroelectric crystalline material selected from the group consisting of titanium oxide (TiO x ), hafnium titanium oxide (HfTiO x ), and hafnium silicon oxide (HfSiO x ) and doped with at least one metal selected from the group consisting of gadolinium, lanthanum, vanadium, phosphorus, potassium, scandium, rubidium, selenium, tin, magnesium, calcium, barium, and indium.   
     
     
         7 . A ferroelectric memory device including memory cells, each of the memory cells, comprising:
 at least one electrode; and   a ferroelectric crystalline material disposed proximate the at least one electrode and polarizable by an electric field generated by the at least one electrode in an electrically charged state, the ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center, the ferroelectric crystalline material selected from the group consisting of hafnium oxide (HfO x ), zirconium oxide (ZrO x ), titanium oxide (TiO x ), hafnium zirconium oxide (HfZrO x ), hafnium titanium oxide (HfTiO x ), and hafnium silicon oxide (HfSiO x ), the ferroelectric crystalline material further including at least one dopant selected from the group consisting of niobium (Nb), tantalum (Ta), lanthanum (La), phosphorus (P), potassium (K), scandium (Sc), rubidium (Rb), selenium (Se), tin (Sn), and indium (In).   
     
     
         8 . A method of forming a semiconductor structure, the method comprising:
 forming a ferroelectric crystalline material over a substrate, the ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center, the ferroelectric crystalline material selected from the group consisting of hafnium oxide (HfO x ), zirconium oxide (ZrO x ), titanium oxide (TiO x ), hafnium zirconium oxide (HfZrO x ), hafnium titanium oxide (HfTiO x ), and hafnium silicon oxide (HfSiO x );   doping the ferroelectric crystalline material with at least one dopant selected from the group consisting of niobium (Nb), tantalum (Ta), lanthanum (La), vanadium (V), phosphorus (P), potassium (K), scandium (Sc), rubidium (Rb), selenium (Se), tin (Sn), and indium (In); and   forming at least one electrode proximate the doped ferroelectric crystalline material.   
     
     
         9 . A semiconductor device, comprising:
 a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center,   wherein the ferroelectric crystalline material comprises a ternary or quaternary oxide material selected from the group consisting of Ti 1.1 Zr 0.893 Hf 0.008 O 4 , Ti 1.92 Ta 1.08 La 3 O 11 , Sr 5 Nb 5 O 16 , ZrMo 2 O 8 , Si 2 Y 2 O 7 , and Ti 0.98 Zr 0.02 RbPO 5 .   
     
     
         10 . The semiconductor device of  claim 9 , wherein the ferroelectric crystalline material has an orthorhombic crystal structure corresponding to a space group selected from the group consisting of Pca2 1 , Pbc2 1 , Pmc2 1 , Pmn2 1 , and Pna2 1 . 
     
     
         11 . The semiconductor device of  claim 10 , wherein the orthorhombic crystal structure has a space group selected from Pca2 1  and Pbc2 1 . 
     
     
         12 . The ferroelectric memory cell of  claim 10 , wherein the orthorhombic crystal structure has a Pmc2 1  space group. 
     
     
         13 . The semiconductor device of  claim 9 , wherein the ferroelectric crystalline material includes at least one dopant selected from the group consisting of yttrium (Y), lanthanum (La), gadolinium (Gd), niobium (Nb), tantalum (Ta), vanadium (V), phosphorus (P), potassium (K), scandium (Sc), rubidium (Rb), selenium (Se), tin (Sn), magnesium (Mg), calcium (Ca), barium (Ba), and indium (In). 
     
     
         14 . The semiconductor device of  claim 9 , wherein a crystal structure of the ferroelectric crystalline material is selected from the group consisting of orthorhombic, tetragonal, cubic, monoclinic, and hexagonal crystal structures. 
     
     
         15 . The semiconductor device of  claim 9 , wherein the ferroelectric crystalline material is at least substantially free of zirconium and hafnium. 
     
     
         16 . The semiconductor device of  claim 9 , wherein the ferroelectric crystalline material is at least one of doped and mechanically strained to prevent formation of inversion symmetry through an inversion center. 
     
     
         17 . The semiconductor device of  claim 9 , wherein the ferroelectric crystalline material comprises a thickness in a range extending from about 2 nm to about 100 nm. 
     
     
         18 . The semiconductor device of  claim 9 , further comprising:
 a source; and   a drain,   wherein the ferroelectric crystalline material is located between the source and the drain.   
     
     
         19 . The semiconductor device of  claim 18 , further comprising an insulating material in contact with the ferroelectric crystalline material and between the source and the drain. 
     
     
         20 . The semiconductor device of  claim 9 , further comprising:
 a first electrode; and   a second electrode,   wherein the ferroelectric crystalline material is located between the first electrode and the second electrode, wherein the first electrode, the second electrode, and the ferroelectric crystalline material comprise a capacitor.   
     
     
         21 . The semiconductor device of  claim 20 , further comprising:
 a source;   a drain; and   a gate electrode between the source and the drain, wherein the capacitor is in electrical communication with the drain.   
     
     
         22 . A method of forming the semiconductor device of  claim 9 , the method comprising:
 forming a ferroelectric crystalline material having a polar and chiral crystal structure without inversion symmetry through an inversion center, wherein the ferroelectric crystalline material does not consist essentially of an oxide of at least one of hafnium (Hf) and zirconium (Zr), wherein the ferroelectric crystalline material comprises a ternary or quaternary oxide material selected from the group consisting of Ti 1.1 Zr 0.893 Hf 0.008 O 4 , Ti 1.92 Ta 1.08 La 3 O 11 , Sr 5 Nb 5 O 16 , ZrMo 2 O 8 , Si 2 Y 2 O 7 , and Ti 0.98 Zr 0.02 RbPO 5 ; and   forming at least one electrode proximate the ferroelectric crystalline material.