Title :
Advanced heterojunction Ge/sub x/Si/sub 1-x//Si bipolar devices
Author :
Taft, R.C. ; Plummer, J.D. ; Iyer, S.S.
Author_Institution :
Center for Integrated Syst., Stanford Univ., CA, USA
Abstract :
The DC characteristics of advanced heterojunction Ge/sub x/Si/sub 1-x/-Si inversion base transistors are presented. Current gains as high as 1720 with a zero bias pinch resistance of R/sub B/=43 k Omega / Square Operator were obtained. This is believed to be the largest room-temperature current gain reported for any Ge/sub x/Si/sub 1-x/ bipolar device to date. In addition, the effects of varying the germanium concentration on both the Gummel plots and current gain versus temperature were explicitly shown. Due to the technological difficulty in obtaining sharp boron doping profiles in this type of bipolar structure, the vertical performance of these Ge/sub x/Si/sub 1-x/ bipolar devices was significantly improved by maximizing the amount of boron dopant in the Ge/sub x/Si/sub 1-x/ base layer.<>
Keywords :
Ge-Si alloys; elemental semiconductors; heterojunction bipolar transistors; semiconductor materials; silicon; B doping profiles; DC characteristics; Ge concentration variation; Ge/sub x/Si/sub 1-x/-Si; GeSi:B base layer; Gummel plots; HBT; bipolar devices; heterojunction inversion base transistors; room-temperature current gain; Boron; Current measurement; Electron emission; Germanium; Heterojunctions; Leakage current; Molecular beam epitaxial growth; Photonic band gap; Silicon; Temperature;
Conference_Titel :
Electron Devices Meeting, 1989. IEDM '89. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0817-4
DOI :
10.1109/IEDM.1989.74365
