LOW-TEMPERATURE PERFORMANCE OF SELF-ALIGNED ETCHED POLYSILICON EMITTER PSEUDOHETEROJUNCTION BIPOLAR-TRANSISTORS

In this paper we present an investigation of the static performance ov er the 300K-80K temperature range of pseudo-heterojunction bipolar tra nsistors using an advanced single-polysilicon CMOS compatible self-ali gned structure and epitaxial growth for the base and the low doped emi tter spacer. These devices exhibit ideal collector currents and non-id eal base currents. By analysing the base leakage current, we have been able to identify the main critical fabrication steps. The bandgap nar rowing in the base has been deduced from the temperature dependence of the collector current and the effect of a parasitic boron spike in th e base doping profile on the low temperature performance of the transi stor has been studied.