High frequency response of p-i-n photodiodes analyzed by an analytical model in Fourier space

A formulation of carrier transport in vertical p-i-n photodiodes is presented in Fourier space, taking into account diffusion effects of carriers outside the intrinsic region. High frequency response of photodiodes is investigated using the model. Calculated results show that diffusion limits the cutoff frequency characteristics of photodiodes with short intrinsic region length. Photocurrent calculations via the spectral method are in excellent agreement with two-dimensional device simulator results. The model can be utilized in circuit simulation because of its reduced computational runtime.