In this paper the influence of the multiplication area shape on the dark count rate (DCR) of InGaAs/InAlAs single-photon avalanche photodiodes (SPADs) is discussed. This study is carried out within the framework of SPAD design parameter optimization. The diode structure has been simulated in the T-CAD calculation environment. The structure with three levels of multiplication area with a smooth transition is the most optimal one. This structure will achieve higher quantum efficiency during the diode operation.