SPEED RESPONSE ANALYSIS OF AN ELECTRON-TRANSFER MULTIPLE-QUANTUM-WELLWAVE-GUIDE MODULATOR

A numerical model is presented for the electronic properties of a nove l InxGa1-xAs/In1-yAlyAs multiple-quantum-well waveguide modulator and a theoretical analysis of electron and hole escape mechanisms from the quantum well is developed. The influence of carriers and dopant ion c harges on the band structure is simulated with a self-consistent Poiss on-Schrodinger solver. The different escape mechanisms for both electr ons and holes are: direct tunneling, phonon-assisted sequential tunnel ing, and thermionic emission. At high forward biases, the electron esc ape time limits the device speed, while at high reverse biases, heavy holes take a longer time than electrons for escaping the quantum well. For both particles, phonon-assisted sequential tunneling is a key mec hanism in determining the device speed operation. The calculated escap e times are in good agreement with the experimental data.