Modeling of InGaAs MSM photodetector for circuit-level simulation

An accurate model for In/sub 0.53/Ga/sub 0.47/As metal-semiconductor-metal (MSM) photodetectors is presented for circuit-level simulation. Dark and dc current characteristics are investigated and modeled. To accurately simulate the large-signal response of MSM photodetectors, impulse response functions and convolution integrals are implemented into SPICE. The transit-time limitation is also incorporated into the small-signal analysis. Most circuit parameters preserve the physical meaning. S-parameter measurements are used to find the circuit parameters critical to transient and ac analyses. Results are compared with experimentally obtained data, and excellent agreement is obtained consistently on InGaAs photodetectors of different sizes.