Bismuth (Author: Lizenz: CC-BY-3.0)Bismuth ferric oxide

Bismuth ferric oxide (BFO) – A special material

Microelectronics and the associated digitalization have changed our everyday-life as well as our work like no other technology before. The key driver is the exponential progress in hardware: According to the so-called Moore’s Law, the integration density of electronic circuits doubles approximately every 18 months. For future innovations this will no longer be sufficient. Here, new materials, termed „More-Than-Moore“, are being required, which complement the CMOS technology. Bismuth ferrite, a bismuth iron oxide (BiFeO3, also: Bismuth ferric oxide, BFO), is such a material with very attractive functionalities.

BFO thin films with metallic electrodes allow non-volatile switching of the resistance or capacitance. The BFO layer possesses a flexible barrier height, which can be adjusted in an analog manner – fast, energy-efficient and long time-stable by applying a voltage pulse. These novel properties unfold without an electroforming step at temperatures up to 120 °C. The technological feasibility of the few necessary process steps for integration into existing CMOS technologies was demonstrated on a semi-industrial scale, on 4″-6″ wafers with CMOS-compatible, metallic conducting electrodes.

As a result, BFO opens up various possibilities for the development of new information and communication technologies based on CMOS. From today’s point of view, the following fields of application can benefit from the material BFO: