Sunday, May 09, 2021

Artilux Dramatically Reduces Ge-on-Si PD Dark Current

Artilux whitepaper presents the company's latest progress in the dark current reduction:

"In this white paper, we proudly announce Artilux Halcyon GeSi Technology, which reduces dark current and DCR by more than 3 orders of magnitude compared to what was commonly known in past literature. Moreover, this breakthrough can be adopted in a wide variety of photodetectors with customized pixel arrays. With such unprecedented performance and attribute, we expect Artilux Halcyon GeSi Technology will soon be applied to multiple growing market segments ranging from NIR and SWIR image sensors, hyperspectral image sensor, 3D and 4D LiDAR sensors and beyond by working with our partners. These markets are estimated to have strong growth with double-digit CAGR (compound annual growth rate) between 2021 to 2025.

To provide a fair comparison to past literature, we fabricated a series of normal incidence photodetectors at various sizes and measured their dark currents. The resulting data with the use of Artilux Halcyon GeSi Technology are shown in Fig. 1.

To evaluate the noise performance of these photodetectors when being used in linear mode or in Geiger-mode photodetection, it’s standard to define the so-called bulk dark current density (unit: mA/cm2) and surface dark current density (unit: μA/cm) and extract them from the data shown in Fig. 1. In past literature, these two numbers were reported roughly in the order of 10 mA/cm2 and 10 μA/cm, respectively. With the use of Artilux Halcyon GeSi Technology, these two numbers can be drastically reduced to roughly a few μA/cm2 and a few nA/cm, respectively, which translates into more than 3 orders
of magnitude improvement!

Halcyon GeSi Technology in conjunction with Artilux proprietary scaling design. For SWIR image sensor with less than 5 μm pixel pitch at low bias voltage typical for this application, the expected performance in pilot run is in the order of a few to tens of fA dark current (uncooled). For direct ToF (time of flight) 3D sensor with slightly larger pixel pitch and around 15V breakdown voltage, the expected performance in pilot run is in the order of tens to hundreds of KHz DCR (uncooled). We will continue to perfect these performances in future Artilux products."

Apparently, the data on the graph shows the previous generation Ge-on-Si dark current:

2 comments:

  1. It is very interesting, however, it is not clear at which bias these data were taken. This makes a big difference when comparing with literature.

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  2. Not only Artilux did not properly mention the voltage at which the dark current was measured, but also the responsivity at certain SWIR wavelength at the same voltage is missing. And what is the overall D* as a standard figure of merit at that operating voltage? The above dark current data is moot.

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