High bandwidth InP/InGaAs based MSM-2DEG diodes for optoelectronic application

In this work the electrical and optoelectronic behavior of InP/InGaAs based MSM diodes above a two dimensional electron gas is investigated. The electric field distribution of this MSM-2DEG device is modified by the two dimensional electron gas, leading to improved performance compared to a conventional MSM diode. An InGaAs layer between the Schottky metallization and the two-dimensional electron gas (2DEG) acts as absorption region for 1.3 to 1.55 /spl mu/m wavelength light. This wavelengths are used for long distance glass fiber communication systems. The substitution of the conventionally used InAlAs by InP avoids the problems related to aluminum (ageing, DX centers, lack of etch control). Photodetectors have been fabricated with responsivities up to 0.61 A/W, at 1.3 /spl mu/m wavelength. RF-optimized devices show bandwidths up to 16 GHz, which is, to the authors´ knowledge, the highest bandwidth reported for MSM photodetectors at this wavelength.