Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Acoustic Wave Amplifier Having a Coupled Semiconductor Layer

IP.com Disclosure Number: IPCOM000074418D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Fang, FF: AUTHOR [+2]

Abstract

This is an amplifier for surface acoustic waves having a region of variable conductivity located in close proximity to the surface on which the acoustic waves travel. A wave propagating piezoelectric medium 10 as input transducer 12 and output transducer 14 located on its top surface 16. Connected to input transducer 12 is a variable-voltage source 18, which excites the input transducer to produce an acoustic wave on surface 16 of medium 10. Located on surface 16 is a semiconductor 20 having an induced inversion layer 22 in contact with the surface. In the example illustrated, semiconductor 20 is of p-type and n-type regions 24 are provided therein. Connected across these n-type regions 24 is a variable voltage source 26 and a series connected resistor 28.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 90% of the total text.

Page 1 of 2

Acoustic Wave Amplifier Having a Coupled Semiconductor Layer

This is an amplifier for surface acoustic waves having a region of variable conductivity located in close proximity to the surface on which the acoustic waves travel. A wave propagating piezoelectric medium 10 as input transducer 12 and output transducer 14 located on its top surface 16. Connected to input transducer 12 is a variable-voltage source 18, which excites the input transducer to produce an acoustic wave on surface 16 of medium 10. Located on surface 16 is a semiconductor 20 having an induced inversion layer 22 in contact with the surface. In the example illustrated, semiconductor 20 is of p-type and n-type regions 24 are provided therein. Connected across these n-type regions 24 is a variable voltage source 26 and a series connected resistor 28. Substrate bias to p-type semiconductor 20 is provided by a voltage source Vb, connected to semiconductor 20 by electrode 30.

The inversion layer 22 is of n-type and formed in a very narrow region on the bottom surface of semiconductor 20. The function of overlying semiconductor 20 is to provide moving charge carriers which create an electric field that interacts with the electric field produced by the traveling acoustic wave on surface 16 of medium 10 in order to transfer energy to or extract energy from the acoustic wave.

For this purpose, charge carrier flow is confined to thin inversion layer 22 adjacent surface 16. Instead of an inversion layer th...