A Scalable 300-GHz Multichip Stitched CMOS Detector Array

A terahertz (THz) CMOS detector array based on multiple chips stitched together is reported. The proposed multichip detector is scalable as the total number of subarray chips is flexible and can be controlled as needed with the help of the modular scheme adopted. Based on the presented multichip technique, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> 3 multichip detector array composed of nine subarray chips has been implemented in this work for operation at 300 GHz. With the subarray chips, each with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7\times $ </tex-math></inline-formula> 7 pixels, the complete multichip array comprises <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$21\times21$ </tex-math></inline-formula> physical pixels. By employing virtual pixels, which are included to compensate for the chip interface area consumed for interchip wire-bonding in this work, THz real-time images with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$23\times23$ </tex-math></inline-formula> pixels have been successfully acquired. The distribution of the responsivity and noise equivalent power (NEP) over the multichip array is presented. The responsivity distribution shows the effect of the series resistance of the long bias lines stretched over the multichip array, while the effect is not apparent for NEP. The distribution due to series resistance, as well as other nonuniformities over the pixels and chips due to various causes, can be suppressed with a proper calibration for the images acquired with the multichip array.