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

Si/SiGe resonant interband tunnel diodes (RITD) were fabricated using CVD on 200-mm silicon wafers. The RITD devices consist of a p⁺-i-n⁺ 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 Jp and peak-to-valley current ratio (PVCR) was studied. As the flow rate is reduced, Jp 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 Jp recorded was 600 A/cm². This is the highest reported PVCR for any CVD-grown Si/SiGe RITD.