Wide frequency band detection on laterally constricted GaAs structures having nanometric heavily doped layers

Abstract

Experimental results of planar asymmetrically and symmetrically shaped hot carrier microwave detectors having five delta-doped GaAs layers are presented. The results are compared with the detectors having the same geometrical shape but only homogeneously doped GaAs layer of submicrometric thickness. DC measurements showed that the structure with delta-doped layers had slightly lower resistance than the detector with homogeneously doped layer due to higher carrier mobility in the delta-doped structure. Increase in carrier mobility corresponded to higher voltage sensitivity, which is essential parameter of a microwave detector. Voltage power characteristics of the detectors of both types were linear up to 10 mW of microwave power, whereas at higher powers they became super-linear or sub-linear with the following change in polarity of the detected voltage. Distinctive dependence of the detected voltage on microwave power at strong electric field is attributed to intervalley transfer of charge carriers. Experimental results of voltage sensitivity in microwave frequency range showed that drop-off of sensitivity going from Ka range to W range for both types of detectors is not larger than 3 dB, suggesting their use for wide frequency detection.