Capacitor insulating film, capacitor, and semiconductor device
View Patent ↗A capacitor insulating film for use as an insulating film sandwiched between two electrodes is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a strontium titanate or barium strontium titanate.
1. A capacitor insulating film for use as an insulating film sandwiched between two electrodes, wherein the capacitor insulating film is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a strontium titanate or barium strontium titanate.
2. The capacitor insulating film according to claim 1 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.1.
3. The capacitor insulating film according to claim 1 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.3.
4. The capacitor insulating film according to claim 1 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.3 and at most 0.8.
5. A capacitor comprising:
a first electrode;
a second electrode opposite to the first electrode; and
an insulating film sandwiched between the first electrode and the second electrode,
wherein the insulating film is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a strontium titanate or barium strontium titanate.
6. The capacitor according to claim 5 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.1 in the crystal forming the insulating film.
7. The capacitor according to claim 5 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.3 in the crystal forming the insulating film.
8. The capacitor according to claim 5 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.3 and at most 0.8 in the crystal forming the insulating film.
9. The capacitor according to claim 8 , wherein the insulating film is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a strontium titanate, and a ratio of the strontium element to a sum of the titanium element and the hafnium element [Sr/(Hf+Ti)] is at least 0.85 and at most 1.15 in the crystal forming the insulating film.
10. The capacitor according to claim 8 , wherein the insulating film is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a barium strontium titanate, and a ratio of a sum of the strontium element and the barium element to a sum of the titanium element and the hafnium element [(Sr+Ba)/(Ti+Hf)] is at least 0.85 and at most 1.15 in the crystal forming the insulating film.
11. A semiconductor device comprising a MOS transistor and a capacitor,
wherein the capacitor comprises:
a first electrode,
a second electrode opposite to the first electrode, and
an insulating film sandwiched between the first electrode and the second electrode;
the insulating film is made of a crystal containing a hafnium element in a titanium site in place of a part of titanium elements contained in a crystal of a strontium titanate or barium strontium titanate; and
one of a source electrode and a drain electrode of the MOS transistor is electrically connected to the first electrode of the capacitor.
12. The semiconductor device according to claim 11 , wherein a ratio of the hafnium element to a sum of the titanium element and the hafnium element [Hf/(Hf+Ti)] is at least 0.3 and at most 0.8 in the crystal forming the insulating film.