Parametric excitaiton of ultrasonic waves in piezoelectric semiconductors

1973 ◽  
Vol 44 (4) ◽  
pp. 1497-1498 ◽  
Author(s):  
Predhiman K. Kaw
Keyword(s):  
Ultrasonic Waves ◽  
Piezoelectric Semiconductors

scholarly journals Localized nonlinear waves in a semiconductor with charged dislocations

2021 ◽  
Vol 250 ◽  
pp. 03012
Author(s):  
Vladimir I. Erofeev ◽  
Anna V. Leonteva ◽  
Alexey O. Malkhanov ◽  
Ashot V. Shekoyan
Keyword(s):  
Electric Field ◽  
Evolution Equation ◽  
Ultrasonic Wave ◽  
Nonlinear Waves ◽  
Piezoelectric Properties ◽  
Exact Analytical Solution ◽  
Constant Electric Field ◽  
Ultrasonic Waves ◽  
Wave Dynamics ◽  
Piezoelectric Semiconductors

To describe a nonlinear ultrasonic wave in a semiconductor with charged dislocations, an evolution equation is obtained that generalizes the well-known equations of wave dynamics: Burgers and Korteweg de Vries. By the method of truncated decompositions, an exact analytical solution of the evolution equation with a kink profile has been found. The kind of kink (increasing, decreasing) and its polarity depend on the values of the parameters and their signs. An ultrasonic wave in a semiconductor containing numerous charged dislocations is considered. It is assumed that there is a constant electric field that creates an electric current. The situation is similar to the case of the propagation of ultrasonic waves in piezoelectric semiconductors, but in the problem under consideration, instead of the electric field due to the piezoelectric properties of the medium, the electric field of dislocations appears.

"Escherichia coli-milk" Biofilm Removal from Stainless Steel Surfaces: Synergism between Ultrasonic Waves and Enzymes

Biofouling ◽  
2003 ◽  
Vol 19 (3) ◽  
pp. 159-168 ◽  
Author(s):  
Nadia Oulahal- Lagsir ◽  
Adele Martial- Gros ◽  
Marc Bonneauc ◽  
Loic Bluma
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Ultrasonic Waves ◽  
Biofilm Removal ◽  
Steel Surfaces

" Escherichia coli -milk" Biofilm Removal from Stainless Steel Surfaces: Synergism between Ultrasonic Waves and Enzymes

Biofouling ◽  
2003 ◽  
Vol 19 (3) ◽  
pp. 159-168 ◽  
Author(s):  
NADIA OULAHAL-LAGSIR ◽  
ADELE MARTIAL-GROS ◽  
MARC BONNEAU ◽  
LOIC BLUM
Keyword(s):  
Escherichia Coli ◽  
Stainless Steel ◽  
Ultrasonic Waves ◽  
Biofilm Removal ◽  
Steel Surfaces

Failure Analysis of Flip-Chip Interconnections Through Acoustic Microscopy

1996 ◽  
Author(s):  
O. Diaz de Leon ◽  
M. Nassirian ◽  
C. Todd ◽  
R. Chowdhury
Keyword(s):  
Failure Analysis ◽  
Large Scale ◽  
Flip Chip ◽  
Ultrasonic Waves ◽  
Acoustic Microscopy ◽  
Acoustic Microscope ◽  
Chip Technology ◽  
Ball Joints ◽  
Non Destructive ◽  
Scanning Acoustic Microscope

Abstract Integration of circuits on semiconductor devices with resulting increase in pin counts is driving the need for improvements in packaging for functionality and reliability. One solution to this demand is the Flip- Chip concept in Ultra Large Scale Integration (ULSI) applications [1]. The flip-chip technology is based on the direct attach principle of die to substrate interconnection.. The absence of bondwires clearly enables packages to become more slim and compact, and also provides higher pin counts and higher-speeds [2]. However, due to its construction, with inherent hidden structures the Flip-Chip technology presents a challenge for non-destructive Failure Analysis (F/A). The scanning acoustic microscope (SAM) has recently emerged as a valuable evaluation tool for this purpose [3]. C-mode scanning acoustic microscope (C-SAM), has the ability to demonstrate non-destructive package analysis while imaging the internal features of this package. Ultrasonic waves are very sensitive, particularly when they encounter density variations at surfaces, e.g. variations such as voids or delaminations similar to air gaps. These two anomalies are common to flip-chips. The primary issue with this package technology is the non-uniformity of the die attach through solder ball joints and epoxy underfill. The ball joints also present defects as open contacts, voids or cracks. In our acoustic microscopy study packages with known defects are considered. It includes C-SCAN analysis giving top views at a particular package interface and a B-SCAN analysis that provides cross-sectional views at a desired point of interest. The cross-section analysis capability gives confidence to the failure analyst in obtaining information from a failing area without physically sectioning the sample and destroying its electrical integrity. Our results presented here prove that appropriate selection of acoustic scanning modes and frequency parameters leads to good reliable correlation between the physical defects in the devices and the information given by the acoustic microscope.

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