  Small spin-qubit registers defined by single electrons confined in Si/SiGe
quantum dots operate successfully and connecting these would permit scalable
quantum computation. Shuttling the qubit carrying electrons between registers
is a natural choice for high-fidelity coherent links provided the overhead of
control signals stays moderate. Our proof-of-principle demonstrates shuttling
of a single electron by a propagating wave-potential in an electrostatically
defined 420 nm long Si/SiGe quantum-channel. This conveyor-mode shuttling
approach requires independent from its length only four sinusoidal control
signals. We discuss the tuning of the signal parameters, detect the smoothness
of the electron motion enabling the mapping of potential disorder and observe a
high single-electron shuttling fidelity of $99.42\pm0.02\,\%$ including a
reversal of direction. Our shuttling device can be readily embedded in
industrial fabrication of Si/SiGe qubit chips and paves the way to solving the
signal-fanout problem for a fully scalable semiconductor quantum-computing
architecture.
