  We propose to create a biexciton by a coherent optical process using a
frequency-sweeping (chirped) laser pulse. In contrast to the two-photon Rabi
flop scheme, the present method uses the state transfer through avoided level
crossing and is a geometric control. The proposed process is robust against
pulse area uncertainty, detuning, and dephasing. The speed of the adiabatic
operation is constrained by the biexciton binding energy.
