Title :
Mechanically strained Si-SiGe HBTs
Author :
Yuan, F. ; Jan, S.-R. ; Maikap, S. ; Liu, Y.-H. ; Liang, C.-S. ; Liu, C.W.
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
fDate :
7/1/2004 12:00:00 AM
Abstract :
The current gain (β=IC/IB) variations of the mechanically strained Si-SiGe heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) devices are investigated experimentally and theoretically. The β change of HBT is found to be 4.2% and -7.8 under the biaxial compressive and tensile mechanical strain of 0.028%, respectively. For comparison, there are 4.9% and -5.0 β variations for BJT under the biaxial compressive and tensile mechanical strain of 0.028%, respectively. In HBT, the mechanical stress is competing with the compressive strain of SiGe base, inherited from the lattice misfit between SiGe and Si. The current change due to externally mechanical stress is the combinational effects of the dependence of the mobility and the intrinsic carrier concentration on strain.
Keywords :
compressive testing; heterojunction bipolar transistors; semiconductor device measurement; semiconductor device testing; Si-SiGe; biaxial compressive strain; bipolar junction transistor; current gain variation; heterojunction bipolar transistor; intrinsic carrier concentration; lattice misfit; mechanical stress; tensile mechanical strain; Bipolar transistors; Boron; Capacitive sensors; Compressive stress; Germanium silicon alloys; Helium; Heterojunction bipolar transistors; Lattices; Silicon germanium; Tensile strain; BJT; Bipolar junction transistor; HBT; heterojunction bipolar transistor; mechanical strain;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2004.831223
