The history and development of the helium ion microscope

The helium ion microscope has recently emerged as a commercially available instrument. However, its roots go back more than 60 years to the development of the field ion microscope in Berlin, first reported in 1951. Over the intervening years, numerous researchers have pursued the development of a gas field ionization source with the goal of producing a suitable source for an ion microscope. This proved to be an elusive goal until early in this century when a number of discoveries led to a successful source, and shortly thereafter, an instrument fully able to exploit its advantages. Many individuals and many technical advances have come together to make this new class of microscope. The long history of this quest is reviewed along with the recent advances that led to the achievement of this milestone. A brief summary of the current status of the technology and its applications are given.