Scanning probes as a lithography tool for nanostructures

Abstract

The transistor has evolved into the first nanoscale device. The most common form is a simple switch, the field effect transistor (FET). The modern FET qualifies as a nanoscale device since the length of the gate region is only 250 nm. In 4 years time this dimension will be scaled down to 100 nm. There are three million FETs in the Pentium. The next generation will contain ten million. The FET has slowly evolved through improvements in optical lithography. We all await the technology set that will push these devices below the classical limits and on to the world of devices that relies on the quantum behavior of electrons. That transition will take place when the device dimensions are reduced below 50 nm. It is a world beyond the reach for optical lithography. Devices with these dimensions will require a revolutionary change in the fabrication process. It is not yet how these devices will be incorporated into systems but it is clear that we will soon have the new technology set needed to fabricate multiple copies of the nanoscale structures. We will present the case for a new technology set based on the scanning probes. Over the past decade scanning probe microscopes have enjoyed widespread acceptance in many areas of science and technology. It is evident from other discussions in this Conference that the probe microscopes are used to gain new knowledge of surface structure and molecular organization in the fields of physics, chemistry and biology. They have also been used as an essential tool in new forms of devices for hi-density storage of digital data. More recently the probes have been used to fabricate nanoscale structures such as field effect and single electron transistors. We will finish by discussing the research now underway for increasing the throughput. The research is proceeding on two fronts. First, the scanning speed is being improved with new designs for the probe, itself. Second, the number of probes are being increased through the fabrication of multiple probes to form arrays of parallel cantilevers with integrated tips.