Auger Spectroscopy and the Chemistry of Defects
Modern consumer electronics are constantly subjected to all types of environmental abuse. They may operate in humid climates, with plenty of ambient moisture that can collect on sensitive circuits. Dust and other particulates can be sucked in by air intakes, introducing any number of organic contaminants onto a device. There is also the omnipresent danger of sugary, carbonated beverages – one of the most diabolical nemeses of electronics in the home, especially a home populated with children (or clumsy adults). All of these things can cause an electronic device to malfunction; fortunately, Auger spectroscopy can help an analyst determine whether these factors are truly the root cause of a given problem.
The physics of Auger spectroscopy have previously been discussed, but a quick summary is as follows: a sample is bombarded with a high energy electron beam, which causes the sample to emit (among multiple other particles) Auger electrons. These Auger electrons have unique characteristic energy levels depending on the type of atom they originated from; by analyzing these energy levels, the elemental makeup of a given sample can be determined. Unlike techniques like x-ray fluorescence (XRF) which can penetrate into the bulk of a sample, Auger spectroscopy is purely a surface analysis technique – making it perfect for analyzing contaminants on a failing device.
Though its high degree of spatial resolution and sensitivity make Auger spectroscopy a perfect tool for analyzing contaminants, it can be used easily for many other purposes as well. When performing a construction analysis on a new product, for example, it may be very useful to determine whether all the constituent components of the device – the layers on an integrated circuit, the various solders and metal traces on a printed circuit board, et cetera – meet the necessary material specifications. Indeed, on many modern integrated circuits, Auger spectroscopy is one of the only tools that is precise enough to characterize the elemental makeup of the infinitesimal features that make up the transistors that give the device its brainpower.
Auger spectroscopy’s adaptability makes it applicable to many different situations: not only can it easily pick up the carbon, oxygen, and phosphorus left behind by the accidental spill of a certain name-brand soft drink that ended the life of a TV remote, it is also perfect for characterizing the construction of integrated circuits and printed circuit boards. This versatility makes it a valuable addition to the failure analyst’s toolbox; since one never knows what the next failing sample to come in will be, it is always necessary to have tools that can be used in a wide variety of ways to uncover the root cause of failure.
Derek Snider is a failure analyst at Insight Analytical Labs, where he has worked since 2004. He is currently an undergraduate student at the University of Colorado, Colorado Springs, where he is pursuing a Bachelors of Science degree in Electrical Engineering.