Voltage tunable oscillator using bilayer graphene and a lead zirconate titanate capacitor

Patent metadata

Field	Value
Publication number	US-9252704-B2
Application number	US-201213471490-A
Country	US
Kind code	B2
Filing date	May 15, 2012
Priority date	May 20, 2011
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A voltage controlled oscillator comprising a substrate and a bilayer graphene transistor formed on the substrate. The transistor has two signal terminals and a gate terminal positioned in between the signal terminals. A voltage controlled PZT or MEMS capacitor is also formed on the substrate. The capacitor is electrically connected to the transistor gate terminal. At least one component is connected to the transistor and capacitor to form a resonant circuit.

First claim

We claim:

1. A voltage controlled oscillator comprising: a substrate, a voltage controlled variable capacitor comprising a layer of lead zirconate titanate (PZT) deposited on the substrate, a transistor comprising a layer of bilayer graphene formed on the same substrate as the PZT layer, and at least one component connected to said transistor and said voltage controlled variable capacitor to form a resonant circuit, wherein a first voltage applied to the voltage controlled variable capacitor adjusts piezoelectric and ferroelectric properties of the PZT layer so that capacitance of the voltage controlled variable capacitor thereof is varied, and varies an output frequency of the resonant circuit, and a second voltage applied to the transistor adjusts energy band gap of the bilayer graphene layer.

2. The voltage controlled oscillator as defined in claim 1 , further comprising:
two signal terminals formed on the bilayer graphene layer.

3. The voltage controlled oscillator as defined in claim 2 further comprising: an insulating layer deposited on the bilayer graphene layer, and a gate terminal formed on, and being insulated from the bilayer graphene layer, the insulating layer.

4. The voltage controlled oscillator as defined in claim 3 , wherein the insulating layer comprises aluminum nitride (AlN) which is deposited directly on the bilayer graphene layer.

5. The voltage controlled oscillator as defined in claim 1 , wherein said at least one component comprises an inductor.

6. A method of forming the voltage controlled oscillator of claim 1 , comprising: forming the voltage controlled variable capacitor including a step of depositing the layer of lead zirconate titanate (PZT) on the substrate; forming the transistor including a step of depositing the layer of bilayer graphene on the same substrate as the PZT layer; and connecting the at least one component to said transistor and said voltage controlled variable capacitor to form the resonant circuit.

7. A method of operating the voltage controlled oscillator of claim 1 , comprising: varying an applied voltage to the PZT layer of the voltage controlled variable capacitor so that the capacitance thereof is varied to vary the output frequency of the resonant circuit.

8. The voltage controlled oscillator as defined in claim 1 , wherein the layer of PZT of the voltage controlled variable capacitor is:
(i) deposited on the substrate adjacent to the bilayer graphene layer; or
(ii) deposited on the bilayer graphene layer with flip-chip bonding.

9. The voltage controlled oscillator as defined in claim 1 , wherein the transistor comprises a layer of lead zirconate titanate (PZT).

10. The voltage controlled oscillator as defined in claim 1 , wherein the voltage controlled variable capacitor is electrically connected to gate terminal of the transistor.

Assignees

• Nayfeh Osama M
• Kilpatrick Stephen James
• Wilson James
• Dubey Madam
• Polcawich Ronald G
• Us Army

Inventors

• Nayfeh Osama M
• Kilpatrick Stephen James
• Wilson James
• Dubey Madam
• Polcawich Ronald G

Classifications

• H10D1/682

  having dielectrics comprising perovskite structures · CPC title

• B82Y10/00

  Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic · CPC title

• H01L28/55

  Electricity · mapped topic

• H01L51/0045

  Electricity · mapped topic

• H01L51/0558

  Electricity · mapped topic