SiGe HBTs for application in BiCMOS technology: I. Stability, reliability and material parameters

Abstract

Extensive work has been done on the SiGe HBTs for BiCMOS applications recently. The work on stability, reliability, simulation and material parameters is critically examined and reviewed in this part of the review. The work on the design, technology and performance of the HBTs will be discussed in part II of the review.

Self-aligned Ti germanosilicide formation on a polycrystalline Si/SiGe/Si extrinsic base for SiGe heterojunction bipolar transistors

“…Figure 8 is the TEM image of the base contact region in the SiGe HBT having the standard base layer. It reveals that there was considerable removal of Ti(Si 1-x Ge x ) 2 and lower oxide during contact window opening in a mixture of RIE gases of CF 4 and CF 3 H. The conformal deposition of metal may be unfeasible on the rugged surface at the contact window so that the contact resistivity will increase. Moreover, as the local distribution and the depth of Ti(Si 1-x Ge x ) 2 protrusions were straggling, the standard deviation of the contact resistivity was large.…”

“…Meanwhile, the base of the SiGe HBT is not a single SiGe layer but has a sandwich structure composed of a Si cap layer, a SiGe layer, and a Si seed layer. This composition is adopted because the Si cap layer enhances the thermal stability of the SiGe layer, 4 and the loading effect can be removed by inserting the Si seed layer. 5 The lower the resistance of the extrinsic base is, the higher the maximum oscillation frequency (f max ) is.…”

IR laser CVD of nanostructured Si/Ge alloy from silane–germane mixture

“…[1,2]). Silicon and germanium are miscible in all proportions and a number of structural varieties of their alloys have been prepared by several techniques.…”

Design and optimization of a buried channel PMOS integrable in a Si1−xGex BiCMOS process

“…Strained Si 1Àx Ge x layers have been extensively pursued to improve the performance of bipolar and CMOS technologies, as strain offers device designers the ability to modify band gap and carrier mobilities [1][2][3][4]. While strained Si 1Àx -Ge x HBT (heterojunction bipolar transistor) has now become the mainstream bipolar technology, progress in the CMOS arena has been relatively slow until now.…”