New approaches to hard bubble suppression

Since the discovery of hard bubbles [1,2], several techniques for their suppression have been reported [3,4]. This paper describes a new double-layer method which is more versatile than previously reported suppression techniques. It is also shown that it may be possible to prevent hard bubble generation without resorting to exchange coupling of multi-layer films. This study has also produced interesting evidence that it is only the generation of hard bubbles that is suppressed, not their existence. The latter result indicates that the existing model of hard bubble suppression [5] is incomplete.