Method of making suspended thin-film semiconductor piezoelectric devices
Abstract
A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.
- Inventors:
-
- Albuquerque, NM
- Cedar Crest, NM
- Issue Date:
- Research Org.:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- OSTI Identifier:
- 873737
- Patent Number(s):
- 6232139
- Assignee:
- Sandia Corporation (Albuquerque, NM)
- Patent Classifications (CPCs):
-
B - PERFORMING OPERATIONS B81 - MICROSTRUCTURAL TECHNOLOGY B81B - MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
H - ELECTRICITY H03 - BASIC ELECTRONIC CIRCUITRY H03H - IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS
- DOE Contract Number:
- AC04-94AL85000
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- method; suspended; thin-film; semiconductor; piezoelectric; devices; process; forming; layer; material; thickness; 10; microns; device; combination; gaas; algaas; layers; form; sensor; electronic; filter; substrate; epitaxially; deposited; 1-5; micron; sacrificial; followed; top; embodiment; selectively; etched; below; reached; selective; etch; removes; acted; stop; leaving; pattern; openings; expose; remove; novel; etchant; solution; containing; surface; tension; reducing; agent; utilized; preventing; buildup; gas; bubbles; otherwise; break; gas bubbles; algaas layer; etch stop; epitaxially deposited; top layer; solution containing; reducing agent; surface tension; gas bubble; piezoelectric material; gaas substrate; gaas layer; selectively etched; thin-film semiconductor; film semiconductor; selective etch; algaas layers; /438/
Citation Formats
Casalnuovo, Stephen A, and Frye-Mason, Gregory C. Method of making suspended thin-film semiconductor piezoelectric devices. United States: N. p., 2001.
Web.
Casalnuovo, Stephen A, & Frye-Mason, Gregory C. Method of making suspended thin-film semiconductor piezoelectric devices. United States.
Casalnuovo, Stephen A, and Frye-Mason, Gregory C. Mon .
"Method of making suspended thin-film semiconductor piezoelectric devices". United States. https://www.osti.gov/servlets/purl/873737.
@article{osti_873737,
title = {Method of making suspended thin-film semiconductor piezoelectric devices},
author = {Casalnuovo, Stephen A and Frye-Mason, Gregory C},
abstractNote = {A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2001},
month = {Mon Jan 01 00:00:00 EST 2001}
}
Works referenced in this record:
X-band thin film acoustic filters on GaAs
journal, January 1993
- Stokes, R. B.; Crawford, J. D.
- IEEE Transactions on Microwave Theory and Techniques, Vol. 41, Issue 6
Piezoelectric photoacoustic study of Al/sub x/Ga/sub 1-x/As epitaxial layer (x=0.22, 0.28, 0.5) grown on semi-insulating GaAs substrate
conference, January 1998
- Fukuyama, A.; Fukuhara, H.; Akashi, Y.
- 1998 IEEE Ultrasonics Symposium. Proceedings (Cat. No. 98CH36102)