Extended wavelength InGaAs infrared detector arrays based on three types of material structures grown by MBE

Abstract

Extended wavelength InGaAs infrared detector arrays in 1.0~2.5μm spectral rang based on three types of material structures grown by MBE were studied. The first type InGaAs detectors, marked by sample 1#, were fabricated using Pi- N epitaxial materials, mesa etching technique, side-wall and surface passivating film. The second type InGaAs detectors, marked by sample 2#, were fabricated using N-i-P epitaxial materials, mesa etching technique, side-wall and surface passivating film. The third type InGaAs detectors, marked by sample 3#, were fabricated using n-i-n epitaxial materials, planar diffusion process and surface passivating coating. I-V curves, low frequency noise and response spectra of these detectors were measured at the different temperature. The response spectra of these detectors cover 1.0~2.5μm wavelength range. The dark current density of three types InGaAs detectors are 28nA/cm², 2μA/cm², 9μA/cm² at 200K and -10mV bias voltage, respectively. Compared to Sample 2# and Sample 3#, sample 1# presents the lower dark current at the same temperature and the same bias voltage, which mainly results in the improvement of surface passivation film and the depth of mesa etching. The frequency spectrum of the noise of sample 1# has an inflection point at about 10Hz frequency, 1/f noise play an obviously role in the detectors below the 10Hz frequency.