Substrate resistivity influence on silicon–germanium phototransistor performance

• Published in: Electronics letters Vol. 55; no. 11; pp. 656 - 658
• Main Authors: Tegegne, Z.G, Nanni, J, Viana, C, Tartarini, G, Polleux, J.-L
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 30.05.2019
• Subjects: bipolar transistor technology; electrical resistivity; elemental semiconductors; frequency 50.0 MHz; Ge‐Si alloys; heterojunction bipolar transistors; high‐resistivity silicon substrate; low‐frequency responsivity; low‐resistivity silicon substrate; LR substrate; Photonics; phototransistors; SiGe phototransistors; SiGe‐Si; SiGe‐Si bipolar technology; silicon; silicon substrate resistivity; silicon–germanium phototransistor performance; substrate resistivity influence; frequency 50.0 MHz; silicon substrate resistivity; Ge-Si alloys; SiGe-Si; high-resistivity silicon substrate; LR substrate; low-resistivity silicon substrate; phototransistors; elemental semiconductors; SiGe-Si bipolar technology; silicon; heterojunction bipolar transistors; substrate resistivity influence; silicon–germanium phototransistor performance; SiGe phototransistors; bipolar transistor technology; electrical resistivity; low-frequency responsivity
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2019.0203

This Letter presents the impact of silicon substrate resistivity on SiGe phototransistors. SiGe phototransistors were fabricated on the commercially available SiGe/Si bipolar technology. The performances of the phototransistors fabricated based on low- and the high-resistive silicon substrate are compared. The phototransistor based on low-resistivity (LR) silicon substrate provides a responsivity of more than double compared to the phototransistor based on a high-resistivity silicon substrate that is fabricated by using the same bipolar transistor technology. The phototransistor fabricated on LR substrate exhibits low-frequency responsivity up to 1.35 A/W (at 50 MHz).