title: Mechanical Flip-Chip for Ultra-High Electron Mobility Devices.
abstract: Electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. This approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility.
authors.affiliation: Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.
authors.forename: Keyan
authors.initials: K
authors.lastname: Bennaceur
authors.affiliation: Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Schmidt
authors.affiliation: Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.
authors.forename: Samuel
authors.initials: S
authors.lastname: Gaucher
authors.affiliation: Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.|Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185 USA.
authors.forename: Dominique
authors.initials: D
authors.lastname: Laroche
authors.affiliation: Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185 USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lilly
authors.affiliation: Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185 USA.
authors.forename: John L
authors.initials: JL
authors.lastname: Reno
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, NJ 08540 USA.
authors.forename: Ken W
authors.initials: KW
authors.lastname: West
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, NJ 08540 USA.
authors.forename: Loren N
authors.initials: LN
authors.lastname: Pfeiffer
authors.affiliation: Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gervais