A 100nm Emitter Transistor Fabricated with Direct EB Writing for High-Speed Bipolar LSIs

In recent years. the performance of bipolar transistors has been improved through the use of down-scaling and polysilicon base technologies. However. scaling down to under a quarter of a micron has been found to be very difficult because of the need for precise control of emitter size and junction depth In response to this problem a now transistor structure is considered to study the limitations of down-scaling as well as to obtain a better understanding of the possibilities of future bipolar transistors. This transistor has a minimum emitter width of lOOnm and was fabricated using electron-beam (EB) lithography and polysilicon base/emitter technologies. as shown in Fig.l. These technologies will be essential for future transistors. Since the emitter width accuracy was ±0.05 (μm(3σ) for the transistor (1). the effect of an ultra-narrow emitter on transistor characteristics was examined.