A Novel Vector Hydrophone Based on the Piezoresistive Effect of Resonant Tunneling Diode

This letter reports a novel vector hydrophone based on the piezoresistive effect of resonant tunneling diode (RTD). An external pressure introduces stress in the layers of RTD and induces its current-voltage (I-V) curves change. This effect has been applied to designing new sensor. By control-hole technology, the sensor is processed integrated with GaAs/In
_x
Ga
_1-x
As/AlAs double barrier structures posited on its strain-sensitive region. The fabricated sensor is packaged for watertight solution, and underwater measurements are conducted in RTD's negative differential resistance (NDR) region. Directivity curve of the sensor follows ";8"; cosine functional form, which shows its vector sound signal detection ability, and its sensitivity reaches -184.6 dB (0 dB = 1 V/muPa) at 1 KHz.