Title :
Heterojunction bipolar transistors with SiGe base grown by molecular beam epitaxy
Author :
Pruijmboom, A. ; Slotboom, Jan W. ; Gravesteijn, D.J. ; Fredriksz, C.W. ; van Gorkum, A.A. ; van de Heuvel, R.A. ; van Rooij-Mulder, J.M.L. ; Streutker, G. ; van de Walle, G.F.A.
Author_Institution :
Philips Res. Lab., Eindhoven, Netherlands
fDate :
7/1/1991 12:00:00 AM
Abstract :
High-quality SiGe heterojunction bipolar transistors (HBTs) have been fabricated using material grown by molecular beam epitaxy (MBE). The height of parasitic barriers in the conduction band varied over the wafer, and the influence of these barriers on controller current, early voltage, and cutoff frequency were studied by experiments and simulations. Temperature-dependent measurements were performed to study the influence of the barriers on the effective bandgap narrowing in the base and to obtain an expression for the collector-current enhancement. From temperature-dependent measurements, the authors demonstrate that the collector-current enhancement of the HBTs can be described by a single exponential function with a temperature-independent prefactor.<>
Keywords :
Ge-Si alloys; energy gap; heterojunction bipolar transistors; molecular beam epitaxial growth; semiconductor materials; HBT; MBE; SiGe base; bandgap narrowing; collector-current enhancement; conduction band; controller current; cutoff frequency; early voltage; heterojunction bipolar transistors; molecular beam epitaxy; parasitic barriers; temperature-dependent measurements; Conducting materials; Cutoff frequency; Germanium silicon alloys; Heterojunction bipolar transistors; Molecular beam epitaxial growth; Performance evaluation; Photonic band gap; Silicon germanium; Temperature measurement; Voltage control;
Journal_Title :
Electron Device Letters, IEEE
