A FPGA or ASIC is usually made from transistors. Transistors usually contain a p-type and n-type doped semiconductor.
Doping means adding an impurity to the semiconductor.

A good p-type semiconductor for printing is Copper(II) Oxide.
A good n-type semiconductor for printing is Tin Dioxide.

To print, a mixture must be made using the oxides. On the reprap wiki [1], bitumen is used. An
alternative may be pine tar.

[1] http://www.reprap.org/wiki/ConductiveMaterials