Maskless fabrication of JFETs via focused ion beams

The creation of active devices utilizing solely FIB fabrication is investigated in this paper. JFETs are constructed using FIB techniques on a mesa of n-type silicon situated atop a layer of silicon dioxide. The source and drain regions are implanted using a beam of singly-charged arsenic ions accelerated to 120 kV. The gate is implanted with singly-charged boron ions at 10 kV. The source, gate, and drain contacts are directly written by FIB using a 30 kV gallium ion beam. FIB deposited platinum forms an ohmic contact to heavily doped silicon, with an average contact resistance of 9.17/spl times/10/sup -3/ /spl Omega/-cm/sup 2/. The CV characteristics of JFET with FIB-fabricated dopants and contacts are illustrated.