Title :
A comprehensive study of lateral and vertical current transport in Si/Si/sub 1-x/Ge/sub xSi HBT´s
Author :
Matutinovic-Krstelj, Z. ; Venkataraman, V. ; Prinz, E.J. ; Sturm, J.C. ; Magee, C.W.
Author_Institution :
Dept. of Electr. Eng., Princeton Univ., NJ, USA
Abstract :
We studied the effects of heavy doping and Ge concentration in the base on the dc performance of Si/Si/sub 1-x/Ge/sub xSi npn HBT´s. The lateral drift mobility of holes in heavily doped epitaxial SiGe bases is found to be lower than bulk Si values and independent of Ge content, and the Hall scattering factor is less than unity and decreases with increasing Ge concentration. For the vertical electron transport we have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration. Finally, a model for the collector current enhancement with respect to Si devices, including the effects of reduced density of states in the strained Si/sub 1-x/Ge/sub x/ base and the effective bandgap due to Ge and heavy doping, is presented.<>
Keywords :
Ge-Si alloys; Hall effect; carrier mobility; elemental semiconductors; energy gap; heavily doped semiconductors; heterojunction bipolar transistors; semiconductor materials; silicon; DC performance; Ge concentration; Hall scattering factor; Si-SiGe-Si; Si/Si/sub 1-x/Ge/sub xSi npn HBTs; bandgap narrowing; collector current; density of states; heavily doped epitaxial bases; lateral current transport; lateral hole drift mobility; strained base; vertical current transport; Charge carrier processes; Doping profiles; Electrons; Germanium silicon alloys; Hall effect; Heterojunction bipolar transistors; Photonic band gap; Scattering; Semiconductor process modeling; Silicon germanium;
Conference_Titel :
Electron Devices Meeting, 1993. IEDM '93. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-1450-6
DOI :
10.1109/IEDM.1993.347392
