  The recent observation of fractional quantum Hall effect in high mobility
suspended graphene devices introduced a new direction in graphene physics, the
field of electron-electron interaction dynamics. However, the technique used
currently for the fabrication of such high mobility devices has several
drawbacks. The most important is that the contact materials available for
electronic devices are limited to only a few metals (Au, Pd, Pt, Cr and Nb)
since only those are not attacked by the reactive acid (BHF) etching
fabrication step. Here we show a new technique which leads to mechanically
stable suspended high mobility graphene devices which is compatible with almost
any type of contact material. The graphene devices prepared on a
polydimethylglutarimide based organic resist show mobilities as high as 600.000
cm^2/Vs at an electron carrier density n = 5.0 10^9 cm^-2 at 77K. This
technique paves the way towards complex suspended graphene based spintronic,
superconducting and other types of devices.
