Boron Delta-Doping Dependence on Si/SiGe Resonant Interband Tunneling Diodes Grown by Chemical Vapor Deposition

Abstract

Si/SiGe resonant interband tunnel diodes (RITD) were fabricated using CVD on 200-mm silicon wafers. The RITD devices consist of a p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -i-n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> structure with δ-doped quantum wells providing resonant interband tunneling through a nominally intrinsic Si/SiGe region. The vapor-phase doping technique was used to obtain abrupt degenerate doping profiles. The boron doping in the δ-doped region was varied, and its effect on peak current density <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Jp</i> and peak-to-valley current ratio (PVCR) was studied. As the flow rate is reduced, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Jp</i> was found to reduce while the PVCR initially increases and then decreases. Device simulations were performed using the ATLAS simulator developed by SILVACO to interpret the results. A maximum PVCR of 2.95 was obtained, and the highest <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Jp</i> recorded was 600 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . This is the highest reported PVCR for any CVD-grown Si/SiGe RITD.