  Spin qubits in Silicon quantum dots can have long coherence times, yet their
manipulation relies on the exchange interaction, through which charge noise can
induce decoherence. Charge traps near the interface of a Si heterostructure
lead to fluctuations in the quantum-dot confinement and barrier potentials,
which cause gating errors and two-spin dephasing. We quantify these effects in
Si double quantum dots using a realistic model of noise. Specifically, we
consider both random telegraph noise from a few traps (good for dots grown on
submicron wafers) and 1/f noise from many traps (good for larger wafers
appropriate for quantum dot arrays). We give estimates of gate errors for
single-spin qubit architectures and dephasing in singlet-triplet qubits.
