Method of forming ferroelectric memory device
Provided is a method of forming a ferroelectric memory device including: forming a ferroelectric layer between a gate electrode and a channel layer by a first atomic layer deposition (ALD) process. The first ALD process includes: providing a first precursor during a first section; and providing a first mixed precursor during a second section, wherein the first mixed precursor includes a hafnium-containing precursor and a zirconium-containing precursor. In this case, the ferroelectric layer is directly formed as Hf 0.5 Zr 0.5 O 2 with an orthorhombic phase (O-phase) to enhance the ferroelectric polarization and property.
1. A method of forming a ferroelectric memory device, comprising:
forming a ferroelectric layer between a gate electrode and a channel layer by a first atomic layer deposition (ALD) process, wherein the first ALD process comprises:
providing a first precursor during a first section; and
providing a first mixed precursor during a second section, wherein the first precursor comprises an oxygen-containing precursor, the first mixed precursor comprises a hafnium-containing precursor and a zirconium-containing precursor, and a content ratio of hafnium-containing precursor to zirconium-containing precursor between 4:6 and 6:4, thereby forming the ferroelectric layer having a plurality of oxygen layers and a plurality of mixing Hf/Zr layers stacked alternately.
2. The method according to claim 1 , wherein the channel layer is formed by a second ALD process, and the second ALD process comprises:
providing a second mixed precursor during a third section, wherein the second mixed precursor comprises two precursors that are different from each other;
providing a fourth precursor during a fourth section;
providing a fifth precursor during a fifth section; and
providing a sixth precursor during a sixth section.
3. The method according to claim 2 , wherein the second mixed precursor comprises GaO x and InO x , the fourth precursor comprises H 2 O, the fifth precursor comprises ZnO, and the sixth precursor comprises H 2 O.
4. The method according to claim 1 , wherein the channel layer is formed by a second ALD process, and the second ALD process comprises:
simultaneously providing a second precursor and a third precursor during a third section, wherein the second precursor and the third precursor are different from each other;
providing a fourth precursor during a fourth section;
providing a fifth precursor during a fifth section; and
providing a sixth precursor during a sixth section.
5. The method according to claim 4 , wherein the second precursor comprises GaO x , the third precursor comprises InO x , the fourth precursor comprises H 2 O, the fifth precursor comprises ZnO, and the sixth precursor comprises H 2 O.
6. The method according to claim 1 , wherein the channel layer is formed by a second ALD process, and the second ALD process comprises: performing a plurality of deposition cycles, each deposition cycle sequentially comprising a third section, a fourth section, a fifth section, a sixth section, and a seventh section,
wherein a purge time in the fourth section is less than a purge time in one of the third, fifth, sixth, and seventh sections.
7. The method according to claim 6 , wherein
the third section provides a third precursor comprising GaO x ,
the fourth section provides a fourth precursor comprising InO x ,
the fifth section provides a fifth precursor comprising H 2 O,
the sixth section provides a sixth precursor including ZnO, and
the seventh section provides a seventh precursor including H 2 O.
8. The method according to claim 6 , wherein a ratio of the purge time of the one of the third, fifth, sixth, and seventh sections to the purge time of the fourth section is 5:1.
9. The method according to claim 1 , wherein the ferroelectric layer is Hf x Zr y O z , and x:y:z is 1:1:4.