An integrated lateral tunneling unit

A micromachined device developed to perform displacement-controlled tunneling is described. Its performance was experimentally confirmed. The lateral tunneling unit (LTU), composed of a comb-drive actuator, a tunneling tip, and an opposing wall integrated on the same wafer was fabricated using surface micromachining with only one photomask. Integration of the tip and its opposing wall eliminated coarse positioning of the specimen, and realized a fully micromachined tunneling unit. The lateral configuration is easy to fabricate and suitable for integrating other structures such as an atomic force microscope (AFM) tip. The LTU can be used as an extremely sensitive position detector. Possible applications, such as an accelerometer and an integrated AFM/LTU chip, are discussed