High performance submicron RTD design for mm-wave oscillator applications

An optimization of the resonant tunnelling diode´s design was done in order to increase the high frequency performance by increasing the current density and minimizing the parasitic small signal parameters like series resistance and intrinsic parallel capacitance. The current density increased by thinning the lower doped contact layers (up to J_P ≈ 495 kA/cm²). The modelling of the optimized devices was also successful. It is found that the advantage of higher current density and therefore higher available power density outweighs increased device capacitance due to the removal of the lower doped contact layer with respect to high frequency performance. The optimum RTD design has 50% lower capacitance at similar DC-operating point, 65% higher available RF-power and an increased cut off frequency up to 420 GHz.