Dr.-Ing. Jiri Marek (spokesman)
Dr.-Ing. Michael Offenberg
Dr.-Ing. Frank Melzer
Robert Bosch GmbH Reutlingen
Bosch Sensortec GmbH

Sensitive measuring sensors made of silicon make automobiles safe. But these sensors are also practical for use in mobile phones or GPS navigation systems.
But how can these sensitive components be prepared for the special requirements of consumer electronics?

The answer: They have to be made smaller and be more cost-efficient in the production of large quantities than in the past. Jiri Marek, Michael Offenberg, and Frank Melzer have shown has it’s done. Jiri Marek is Development Manager Sensors, Michael Offenburg Group Manager Application Sensors at Robert Bosch GmbH, Frank Melzer Managing Director of Bosch Sensortec GmbH in Reutlingen.

The Electronic Stability Program (ESP), developed at Bosch and now fitted into most new cars, has drastically reduced the number of fatal car accidents due to skidding. At the heart of the ESP system are micromechanical sensors: minute measuring instruments made of silicon, consisting of movable components and detect skid conditions of the vehicle early enough to allow the car’s technology to take corrective action. New mid-sized class cars have up to one hundred sensors that monitor safety or provide the lowest possible fuel consumption.

In the past, micromechanical sensors were too large, too expensive to be used in portable electronic devices and used too much power. And yet, the developers of electronic devices have long had a number of ideas as to how the sensitive measuring devices can be put to good use.

Using new fabrication techniques, the researchers at Bosch succeeded in getting the sensors into shape for applications outside of the automotive sector. In doing so, they chose surface micromachining as the manufacturing method. In this process, movable structures such as masses and springs are layers onto the surface of a silicon wafer. Using several new processes, such as etching and depositing of material, the researchers laid the foundation which allows surface micromachining to be used for cost-effective industrial production of large quantities of small and economical sensors.

In the meantime, the first products integrating acceleration sensors, for example, are already on the market. They protect laptop hard drives from shock or vibration or allow mobile phone controls to be operated by moving the device. Pressure sensors in GPS navigation devices accurately determine the absolute altitude – the basis for mobile navigation. The potential of the technology is enormous: In 2006, Bosch sales exceeded several hundred million Euros in micromechanical systems for the automotive sector. According to forecasts, through the use of sensors in consumer electronics, sales are expected to double over the next few years.