scholarly journals Design of silicon membranes for ultrasonic transducers and its fabrication by anisotropic wet etching

2020 ◽  
Vol 1697 ◽  
pp. 012100
Author(s):  
S V Malohatko ◽  
E Yu Gusev ◽  
J Y Jityaeva ◽  
O A Ageev
Keyword(s):  
Wet Etching ◽  
Ultrasonic Transducers ◽  
Silicon Membranes

Progress in laser-induced backside wet etching

2010 ◽  
Author(s):  
Hiroyuki Niino ◽  
Tadatake Sato ◽  
Yoshizo Kawaguchi ◽  
Aiko Narazaki ◽  
Ryozo Kurosaki
Keyword(s):  
Wet Etching

A Review of Wet Etch Formulas for Silicon Semiconductor Failure Analysis

1996 ◽  
Author(s):  
T.W. Lee
Keyword(s):  
Failure Analysis ◽  
Literature Search ◽  
Wet Etching ◽  
Second Step ◽  
Environmental Concerns ◽  
Acid System ◽  
Graphical Data ◽  
Selective Etch ◽  
Chromium Compounds ◽  
Wet Etch

Abstract WET ETCHING is an important part of the failure analysis of semiconductor devices. Analysis requires etches for the removal, delineation by decoration or differential etching, and study of defects in layers of various materials. Each lab usually has a collection of favored etch recipes. Some of these etches are available premixed from the fab chemical supply. Some of these etches may be unique, or even proprietary, to your company. Additionally, the lab etch recipe list will usually contain a variety of classical "named etches". These recipes, such as Dash Etch, have persisted over time. Although well-reported in the literature, lab lists may not accurately represent these recipes, or contain complete and accurate instructions for their use. Time seems to have erased the understanding of the purpose of additives such as iodine, in some of these formulas. To identify the best etches and techniques for a failure analysis operations, a targeted literature review of articles and patents was undertaken. It was a surprise to find that much of the work was quite old, and originally done with germanium. Later some of these etches were modified for silicon. Much of this work is still applicable today. Two main etch types were found. One is concerned with the thinning and chemical polishing of silicon. The other type is concerned with identifying defects in silicon. Many of the named etches were found to consist of variations in a specific acid system. The acid system has been well characterized with ternary diagrams and 3-D surfaces. The named etches were plotted on this diagram. The original formulas and applications of the named etches were traced to assure accuracy, so that the results claimed by the original authors, may be reproduced in today's lab. The purpose of this paper is to share the condensed information obtained during this literature search. Graphical data has been corrected for modem dimensions. Selectivities have been located and discussed. The contents of more than 25 named etches were spreadsheeted. It was concluded that the best approach to delineation is a two-step etch, using uncomplicated and well-characterized standard formulas. The first step uses a decoration or differential etch technique to define the junctions. Formulations for effective decoration etches were found to be surprisingly simple. The second step uses a selective etch to define the various interconnections and dielectric layers. Chromium compounds can be completely eliminated from these formulas, to meet environmental concerns. This work, originally consisting of 30 pages with 106 references, has been condensed to conform with the formatting requirements of this publication.

A Novel Junction Profiling Methodology

2010 ◽  
Author(s):  
Tomokazu Nakai
Keyword(s):  
Failure Analysis ◽  
Profile Analysis ◽  
Semiconductor Devices ◽  
Wet Etching ◽  
Two Dimensional ◽  
Electrical Characteristics ◽  
Conventional Methods

Abstract Currently many methods are available to obtain a junction profile of semiconductor devices, but the conventional methods have drawbacks, and they could be obstacles for junction profile analysis. This paper introduces an anodic wet etching-based two-dimensional junction profiling method, which is practical, efficient, and reliable for failure analysis and electrical characteristics evaluation.

Modelling of functionally graded piezoelectric ultrasonic transducers

2007 ◽  
Author(s):  
Wilfredo M. Rubio ◽  
Flavio Buiochi ◽  
Julio C. Adamowski ◽  
Emilio C. N. Silva
Keyword(s):  
Functionally Graded ◽  
Ultrasonic Transducers ◽  
Functionally Graded Piezoelectric

Ultrasonic transducers using PVDF

1991 ◽  
Vol 115 (1) ◽  
pp. 267-278 ◽  
Author(s):  
S. Hurmila ◽  
H. Stubb ◽  
J. Pitkanen ◽  
K. Lahdenpera ◽  
A. Penttinen ◽  
...  
Keyword(s):  
Ultrasonic Transducers

scholarly journals Encapsulation of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for the Acoustic Communication between Medical Implants

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 421
Author(s):  
Jorge Oevermann ◽  
Peter Weber ◽  
Steffen H. Tretbar
Keyword(s):  
Data Security ◽  
Ultrasonic Transducers ◽  
Surrounding Tissue ◽  
Center Frequency ◽  
Medical Implants ◽  
Research Groups ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Polyether Ether Ketone ◽  
High Bandwidth ◽  
Ether Ketone

The aim of this work was to extend conventional medical implants by the possibility of communication between them. For reasons of data security and transmitting distances, this communication should be realized using ultrasound, which is generated and detected by capacitive micromachined ultrasonic transducers (CMUTs). These offer the advantage of an inherent high bandwidth and a high integration capability. To protect the surrounding tissue, it has to be encapsulated. In contrast to previous results of other research groups dealing with the encapsulation of CMUTs, the goal here is to integrate the CMUT into the housing of a medical implant. In this work, CMUTs were designed and fabricated for a center frequency of 2 MHz in water and experimentally tested on their characteristics for operation behind layers of Polyether ether ketone (PEEK) and titanium, two typical materials for the housings of medical implants. It could be shown that with silicone as a coupling layer it is possible to operate a CMUT behind the housing of an implant. Although it changes the characteristics of the CMUT, the setup is found to be well suited for communication between two transducers over a distance of at least 8 cm.

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