Photoluminescence of phosphorus atomic layer doped Ge grown on Si

• Published in: Semiconductor science and technology 2017-10, Vol.32 (10), p.104005
• Main Authors: Yamamoto, Yuji, Nien, Li-Wei, Capellini, Giovanni, Virgilio, Michele, Costina, Ioan, Schubert, Markus Andreas, Seifert, Winfried, Srinivasan, Ashwyn, Loo, Roger, Scappucci, Giordano, Sabbagh, Diego, Hesse, Anne, Murota, Junichi, Schroeder, Thomas, Tillack, Bernd
• Format: Article
• Language: English
• Subjects: atomic layer doping; chemical vapor deposition; epitaxy; gemanium; phosporus; photoluminescence
• ISSN: 0268-1242; 1361-6641
• DOI: 10.1088/1361-6641/aa8499

Improvement of the photoluminescence (PL) of Phosphorus (P) doped Ge by P atomic layer doping (ALD) is investigated. Fifty P delta layers of 8 × 1013 cm−2 separated by 4 nm Ge spacer are selectively deposited at 300 °C on a 700 nm thick P-doped Ge buffer layer of 1.4 × 1019 cm−3 on SiO2 structured Si (100) substrate. A high P concentration region of 1.6 × 1020 cm−3 with abrupt P delta profiles is formed by the P-ALD process. Compared to the P-doped Ge buffer layer, a reduced PL intensity is observed, which might be caused by a higher density of point defects in the P delta doped Ge layer. The peak position is shifted by ∼0.1 eV towards lower energy, indicating an increased active carrier concentration in the P-delta doped Ge layer. By introducing annealing at 400 °C to 500 °C after each Ge spacer deposition, P desorption and diffusion is observed resulting in relatively uniform P profiles of ∼2 × 1019 cm−3. Increased PL intensity and red shift of the PL peak are observed due to improved crystallinity and higher active P concentration.