Enhanced Breakdown Voltage, Diminished Quasi-Saturation, and Self-Heating Effects in SOI Thin-Film Bipolar Transistors for Improved Reliability: A TCAD Simulation Study

Based on an extensive two-dimensional process and device simulation studies, a new n/sup +/-p-n-n/sup +/ vertical submicrometer bipolar junction transistor with a three-zone step doped lateral collector (VSLC) structure is presented. It is demonstrated for the first time that the breakdown voltage of the thin-film (<0.5 /spl mu/m) bipolar transistors can be enhanced significantly by using a combination of a vertical thin base and the VSLC structure. The proposed VSLC structure exhibits: 1) excellent output characteristics; 2) diminished quasi-saturation; 3) improved reliability against self-heating effect; and 4) enhanced breakdown voltage as high as 60% more than that of the conventional thin-film lateral bipolar transistor (LBT) on silicon-on-insulator. It also obviates the difficulties associated with the formation of a thin base in LBTs.