Local laser-induced solid-phase recrystallization of phosphorus-implanted Si/SiGe heterostructures for contacts below 4.2 K

Physical Review Materials, vol. 8

Abstract

Si/SiGe heterostructures are of high interest for high-mobility transistor and qubit applications, specifically for operations below $4.2\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. In order to optimize parameters such as charge mobility, built-in strain, electrostatic disorder, charge noise, and valley splitting, these heterostructures require Ge concentration profiles close to monolayer precision. Ohmic contacts to undoped heterostructures are usually facilitated by a global annealing step activating implanted dopants, but compromising the carefully engineered layer stack due to atom diffusion and strain relaxation in the active device region. We demonstrate a local laser-based annealing process for recrystallization of ion-implanted contacts in SiGe, greatly reducing the thermal load on the active device area. To quickly adapt this process to the constantly evolving heterostructures, we deploy a calibration procedure based exclusively on optical inspection at room temperature. We measure the electron mobility and contact resistance of laser-annealed Hall bars at temperatures below $4.2\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and obtain values similar or superior to that of a globally annealed reference sample. This highlights the usefulness of laser-based annealing to take full advantage of high-performance Si/SiGe heterostructures.

Authors 9

1. Malte Neul Aachen JARA-FIT Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany

2. Isabelle V. Sprave Aachen JARA-FIT Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany

3. Laura K. Diebel

   University of Regensburg

   Affiliation as printed

   Fakultät für Physik, Universität Regensburg, 93040 Regensburg, Germany

4. Lukas G. Zinkl

   University of Regensburg

   Affiliation as printed

   Fakultät für Physik, Universität Regensburg, 93040 Regensburg, Germany

5. Florian Fuchs Aachen Fraunhofer-Institut für Lasertechnik ILT

   Fraunhofer Institute for Laser Technology

   Affiliation as printed

   Fraunhofer-Institut für Lasertechnik ILT, 52074 Aachen, Germany

6. Yuji Yamamoto

   Leibniz Institute for High Performance Microelectronics

   Affiliation as printed

   IHP-Leibniz-Institut für Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany

7. Christian Vedder Aachen Fraunhofer-Institut für Lasertechnik ILT

   Fraunhofer Institute for Laser Technology

   Affiliation as printed

   Fraunhofer-Institut für Lasertechnik ILT, 52074 Aachen, Germany

8. Dominique Bougeard

   University of Regensburg

   Affiliation as printed

   Fakultät für Physik, Universität Regensburg, 93040 Regensburg, Germany

9. Lars R. Schreiber corresponding Aachen JARA-FIT Institute for Quantum Information

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   ARQUE Systems GmbH, 52074 Aachen, Germany

   JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, 52074 Aachen, Germany