A new fabrication process for metallic point contacts

We present a new process to fabricate metallic point contacts. The key feature of this process is the use of a Si membrane. Advantages of the process are i) the possibility to fabricate very small holes (down to 10 nm diameter), while the lithographic resolution requirements are modest, ii) the possibility to fine-tune the size of the hole by thermal oxidation and iii) probably a better controlled filling of the hole due to its tapered shape and its sharp edge. From electrical transport measurements it follows that the process yields highly ballistic point contacts.