Elimination of low frequency gain in InAlAs/InGaAs metal-semiconductor-metal photodetectors by silicon nitride passivation

Abstract

We report the reduction of low frequency gain and surface recombination in InAlAs/InGaAs metal-semiconductor-metal (MSM) photodetectors, by surface passivation with plasma-enhanced chemical vapor deposition (PECVD) of silicon nitride. A corresponding improvement in device speed, measured in the frequency-domain, is demonstrated. Large (100 µm) 2 devices exhibit neartransit-time-limited bandwidth (>10 GHz) following passivation, and device characteristics have been stable over a period of several months. We propose a physical model for electron trapping at the free surface, to explain the low frequency gain in nonpassivated devices and its subsequent elimination.

Room-Temperature Photodetection Dynamics of Single GaN Nanowires

“…This insensitivity of depleted polar NWs to the environment is an attractive feature for reliable and robust photodetector applications. Further improvement of the photodetector time response, going beyond the gain × bandwidth limitation, requires either an adjustment of the device design (e.g., replacing the ohmic contacts by Schottky barriers, which enhance the collection of photogenerated carriers) or a modification of the surface properties via core–shell structure, surface treatment or passivation …”

“…Further improvement of the photodetector time response, going beyond the gain × bandwidth limitation, requires either an adjustment of the device design (e.g., replacing the ohmic contacts by Schottky barriers, 37 which enhance the collection of photogenerated carriers) or a modification of the surface properties via core−shell structure, 38 surface treatment or passivation. 39 Conclusions. Defect-free GaN n−i−n NWs present high photocurrent gain in the range of 10 5 −10 8 .…”

Modeling and analysis of the spectral response for AlGaAs/GaAs HPTs for short wavelength optical communication

“…This data has been obtained by varying the base width in Eqs. (5), (6), and (7) and updating the values of the corresponding currents in Eq. (9) for three wavelengths under investigation.…”

“…5 Metal-semiconductor-metal (MSM), on the other hand, have low capacitance due to Schottky-like contact which make them suitable for high frequency operation but their temperature instability, lack of internal gain and complicated epitaxial growth and fabrication process make their use limited for long wavelength optical receivers. 6 The advantage of HPTs over avalanche photodiodes (APDs) is evident from its low noise operation along with the simple biasing conditions compared to APDs. 7 It is therefore expected that HPTs provide an exciting alternative to the above mentioned devices for the manufacture of high speed optical receiver for both short and long wavelength communication based on HBTs.…”

Improvement of surface leakage current of 2.6 µm InGaAs photodetectors by using inductive coupled plasma chemical vapor deposition technology

“…To obtain the low surface recombination, conventionally, a thermally grown SiN x layer is deposited for passivating the edge surfaces by plasma enhanced chemical vapor deposition (PECVD) technology. 15,16) This technology has the process temperature around 300 °C. An alternative SiN x passivation technology is inductively coupled plasma chemical vapor deposition (ICPCVD) technology.…”