Performance-Enhanced CMOS Polysilicon Microbolometer with Narrow Supporting Arms

The performance of a microbolometer can be significantly impacted by the structure of its supporting arms. In this study, we successfully enhanced the performance of a CMOS microbolometer by reducing the width of its supporting arms through a post-CMOS process. The microbolometer with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3\ μ m</tex> L-type supporting arms demonstrates an ultra-low thermal conductance of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.26× 10⁻⁷W/K</tex> and a maximum responsivity ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Rᵥ</tex> ) of about <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3.96× 10⁴V/W</tex> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">25\ μ A</tex> . The average responsivity of the microbolometer is improved by 66.2% from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13\ μ m</tex> compared to the microbolometer with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5\ μ m</tex> supporting arms. The demonstrated high-performance CMOS microbolometer with narrow supporting arms holds a simple structure and preparation process, which is promising for high-density array integration.