Surface Leakage Behaviors of $2.6~\mu$ m In<sub>0.83</sub>Ga<sub>0.17</sub>As Photodetectors as a Function of Mesa Etching Depth
Yage Liu, Yingjie Ma, Xue Li, Yi Gu, Yonggang Zhang, Haimei Gong, Jiaxiong Fang
Abstract
Dark current behaviors of the 2.6 gm cutoff wavelength In0,83Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0,17</sub> As photodetectors are investigated as a function of the mesa etching depth. The total dark current monotonically declines from 2.0x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 8.3x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-7</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 180 K and -10 mV as the mesa etching depth decreases from 2.6 to 0.9 gm. Meanwhile, an order of magnitude lower surface leakage current from 4.56 to 0.47 nA/cm, and a narrower statistical distribution are observed simultaneously. Moreover, the 300 K peak detectivity and quantum efficiency increase from 2.6x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> to 5.4x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cmHz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> /W and from 67.1% to 71.2%, respectively, as the mesa etching depth decreases from 2.6 to 0.9 gm, benefit from the lateral carrier collection effect. These results suggest shallow mesa structures are indispensable towards surface leakage free In0,83Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0,17</sub> As photodetectors.