EAG Application Solutions for Diffusion

Diffusion is the movement of one material into another. Sometimes this movement is a desired effect, but most of the time it is not. The process usually occurs more rapidly during heating events, and analyses can be done to determine the extent to which diffusion has taken place. The challenge is being sensitive enough to both depth resolution and detection limits, so you can see the diffusion, while simultaneously ensuring that the analysis itself does not affect the result.

Diffusion analysis is usually done using ion beam depth-profiling methods, such as Auger Electron Spectroscopy (Auger) and Secondary Ion Mass Spectrometry (SIMS). The particular technique used depends upon the sample being tested:

• Metal layer inter-diffusion—Auger is generally used for metal layer inter-diffusion analysis because Zalar rotation reduces the sputter etch roughening effects, making for better interface and layer definition.
• Dopant Diffusion—SIMS is generally used for implant studies in semiconductors where the best detection limit and good depth resolution are required.

Barrier Layer Effectiveness

Depth profiling using ion beam etching/sputtering methods can push one material into another material. By using low beam energy and/or analyzing the sample’s backside, you can effectively avoid/reduce ion beam etch artifacts, allowing you to see the true diffusion. Low concentration diffusion can be seen best using SIMS.

Application Notes