Method of making ferrolectric thin film composites

• US 5,766,697 A
• Filed: 11/05/1996
• Issued: 06/16/1998
• Est. Priority Date: 12/08/1995
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Sengupta, Somnath, Sengupta, Louise
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US08/766,704
• Time in Patent Office: 588 Days
• Field of Search: 427/585, 427/596, 427/248.1, 427/586, 427/255.3
• US Class Current: 427/585
• CPC Class Codes: C23C 14/088 of the type ABO3 with A representing alkali, alkaline earth metal or Pb and B representing a refractory or rare earth metal
• CPC Class Codes: C23C 14/28 by wave energy or particle radiation C23C14/32 - C23C14/48 take precedence

Abstract

A method of making ferroelectric thin film composites includes the step ofroviding a barium strontium titanate material with an additive magnesia-based and forming a thin film ferroelectric composite using pulsed laser deposition. The method forms a thin film composite having enhanced electronic properties.

Claims

1. A method of making a thin film of a ferroelectric composite material having a composition comprising:

barium strontium titanate, said barium strontium titanate represented as Ba_1-x Sr_x TiO₃, wherein x is greater than 0.0 but less than or equal to 0.75, and an additive selected from the group consisting of mangesia, alumina, silica, a low dielectric oxide, zirconia, and combinations thereof;

wherein said barium strontium titanate and said additive are present in effective amounts to provide a composite having a low dielectric constant, low loss tangibles, and high tunability.

the method comprising the steps of;

a) providing at least one ceramic disc of said composition as an abalation target;

b) providing a substrate at a temperature of between 400-700 degrees centigrade, and at a distance between the substrate and target of 25-50 mm;

c) depositing a thin file of said composition on said substrate using a krypton exciminer pulsed laser utilizing a laser wavelength of 193-248 nm, a laser pulse energy of 226-350 m/J pulse, a pulse width of 10-20 ns and a pulse repetition rate of 5-25 Hz.

2. The thin film ferroelectric composite material of claim 1, wherein said barium strontium titanate is Ba_1-x Sr_x TiO₃, wherein x=0.35 to 0.40.

3. The thin film ferroelectric composite material of claim 2, wherein the weight ratio of said barium strontium titanate to said additive ranges from approximately 99%-50% barium strontium titanate to approximately 1%-60% additive.

4. The thin film ferroelectric composite of claim 1 wherein said additive is magnesia.

5. The thin film ferroelectric composite of claim 4 wherein said magnesia is about 1%.

6. The thin film ferroelectric composite of claim 1 wherein said additive is alumina.

7. The thin film ferroelectric composite of claim 6 wherein said alumina is about 1%.

8. The thin film ferroelectric composite of claim 1 wherein said additive is zirconia.

9. The thin film ferroelectric composite of claim 8 wherein said zirconia is about 1%.

10. The method of claim 1 wherein a plurality of ceramic discs are used, said plurality making up said composition in total.