TY - JOUR
T1 - Characteristics of Germanium n+/p junctions formed by phosphorus diffusion from on indium-gallium-phosphide layer
AU - Baek, Jung Woo
AU - Shim, Jaewoo
AU - Park, Jin Hong
N1 - Publisher Copyright:
© 2015 Published by Elsevier B.V.
PY - 2015/4/28
Y1 - 2015/4/28
N2 - Although numerous studies have been previously reported for the formation of Ge p-n junctions, there is still a lack of research on Ge junctions formed by solid-phase diffusion doping, which typically uses the diffusion phenomenon of phosphorus (P) atoms from InGaP for the fabrication of a Ge n+/p subcell in a III-V multi-junction cell. Here, we investigate the characteristics of Ge n+/p junctions achieved by the InGaP-based diffusion technique at 450-650 °C with SIMS, ECV, and J-V analyses. In addition, through a multiple error function fitting method, diffusivity, peak position, and activation energy values are accurately estimated from raw In/Ga/P/Ge SIMS profiles. The extracted activation energy values for In/Ga/P atoms are much lower than previously reported, indicating that a faster diffusion phenomenon occurs during the simultaneous diffusion of In/Ga/P into Ge. A non-annealed InGaP-deposited junction shows Ohmic behavior with a high current density because of leakage currents by many interfacial point defects. After a 550 °C anneal, the current density is reduced by 3-4 orders of magnitude and a small on/off-current ratio is obtained. Compared to this 550 °C annealed junction, a current density increases ∼10 times in the 650 °C sample due to an increased n-type carrier concentration.
AB - Although numerous studies have been previously reported for the formation of Ge p-n junctions, there is still a lack of research on Ge junctions formed by solid-phase diffusion doping, which typically uses the diffusion phenomenon of phosphorus (P) atoms from InGaP for the fabrication of a Ge n+/p subcell in a III-V multi-junction cell. Here, we investigate the characteristics of Ge n+/p junctions achieved by the InGaP-based diffusion technique at 450-650 °C with SIMS, ECV, and J-V analyses. In addition, through a multiple error function fitting method, diffusivity, peak position, and activation energy values are accurately estimated from raw In/Ga/P/Ge SIMS profiles. The extracted activation energy values for In/Ga/P atoms are much lower than previously reported, indicating that a faster diffusion phenomenon occurs during the simultaneous diffusion of In/Ga/P into Ge. A non-annealed InGaP-deposited junction shows Ohmic behavior with a high current density because of leakage currents by many interfacial point defects. After a 550 °C anneal, the current density is reduced by 3-4 orders of magnitude and a small on/off-current ratio is obtained. Compared to this 550 °C annealed junction, a current density increases ∼10 times in the 650 °C sample due to an increased n-type carrier concentration.
KW - Ge p-n junction
KW - InGaP
KW - Solid-phase diffusion
UR - http://www.scopus.com/inward/record.url?scp=84928947689&partnerID=8YFLogxK
U2 - 10.1016/j.cap.2015.04.040
DO - 10.1016/j.cap.2015.04.040
M3 - Article
AN - SCOPUS:84928947689
SN - 1567-1739
VL - 15
SP - 765
EP - 769
JO - Current Applied Physics
JF - Current Applied Physics
IS - 7
ER -