Method for determining properties of a film, and apparatus for realizing the method

• US 20060172445A1
• Filed: 07/29/2005
• Published: 08/03/2006
• Est. Priority Date: 01/28/2005
• Status: Active Grant

• Current Assignee: Guo-Tsai Huang, Pei-Zen Chang, Tsung-Tsong Wu, Yung-Yu Chen
• Original Assignee: Guo-Tsai Huang, Pei-Zen Chang, Tsung-Tsong Wu, Yung-Yu Chen
• Inventors: Huang, Guo-Tsai, Chang, Pei-Zen, Chen, Yung-Yu, Wu, Tsung-Tsong
• Granted Patent: US 7,350,416 B2
• Time in Patent Office: Days
• US Class Current: 438/17
• CPC Class Codes: G01N 2291/012 Phase angle
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 29/043 in the interior, e.g. by shear waves
• CPC Class Codes: G01N 29/075 by measuring or comparing phase angle measuring frequencies or phase angles per se G01R23/00, G01R25/00
• CPC Class Codes: G01N 29/22 Details , e.g. general constructional or apparatus details

Abstract

A method for determining properties or a thin film includes the steps of: providing a piezoelectric substrate; providing a slanted finger interdigital transducer unit that includes a transmitter port and a receiver port on the piezoelectric substrate; forming the thin film on the piezoelectric substrate between the transmitter port and the receiver port; applying an input signal to the transmitter port; and measuring a phase difference, which corresponds to the input signal, from the receiver port. Accordingly, properties of the thin film are determined based on the measured phase difference. An apparatus for realizing the method is also disclosed.

Claims

1. A method for determining properties of a thin film, said method comprising the steps of;

A) providing a piezoelectric substrate;

B) providing a slanted finger interdigital transducer unit that includes a first transmitter port and a first receiver port on the piezoelectric substrate;

C) forming the thin film on the piezoelectric substrate between the first transmitter port and the first receiver port;

D) applying an input signal to the first transmitter port; and

E) measuring a phase difference, which corresponds to the input signal applied in step D), from the first receiver port,

wherein properties of the thin film are determined based on the phase difference measured in step E).

2. The method as claimed in claim 1, further comprising the steps of:

G) applying an input signal to the first transmitter port prior to step C); and

H) measuring a phase difference, which corresponds to the input signal applied in step G), from the first receiver port,

wherein the properties of the thin film are further determined based on the phase difference measured in step H).

3. The method as claimed in claim 1, wherein the slanted finger interdigital transducer unit further includes a second transmitter port and a second receiver port, said method further comprising the steps of:

J) applying an input signal co the second transmitter port; and

K) measuring a phase difference, which corresponds to the input signal applied in step J), from the second receiver port;

wherein the properties of the thin film are further determined based on the phase difference measured in step K).

4. The method as claimed in claim 1, wherein the slanted finger interdigital transducer unit further includes a second receiver port, said method further comprising the steps of:

M) measuring a phase difference, which corresponds to the input signal applied in step D), from the second receiver port;

wherein the properties of the thin film are further determined based on the phase difference measured in step M).

5. The method as claimed in claim 1, wherein step C) in performed using one of sputtering technique, thermal evaporation technique, chemical vapor deposition (CVD) technique, and molecular beam epitaxy (MBE) technique.

6. An apparatus for determining properties of a thin film, said apparatus comprising:

a piezoelectric substrate having a surface;

a slanted finger interdigital transducer unit including a first transmitter port and a first receiver port, each of which is provided on said surface of said piezoelectric substrate; and

a mask disposed above said surface of said piezoelectric substrate, and defining a hole therethrough to expose a portion of said surface of said piezoelectric substrate between said first transmitter port and said first receiver port.

7. The apparatus as claimed in claim 6, wherein said piezoelectric substrate further has opposite edges, said apparatus further comprising a pair of acoustic absorbers, each of which is provided on said surface of said piezoelectric surface and is disposed at a respective one of said edges of said piezoelectric substrate.

8. The apparatus as claimed in claim 6, wherein said slanted finger interdigital transducer unit further includes a second transmitter port and a second receiver port.

9. The apparatus as claimed in claim 8, wherein said first transmitter port and said first receiver port defines a first distance therebetween, said second transmitter port and said second receiver port defining a second distance therebetween that is equal to the first distance between said first transmitter port and said first receiver port.

10. The apparatus as claimed in claim 6, wherein said slanted finger interdigital transducer unit further includes a second receiver port.