Low-noise microwave bipolar transistor with sub-half-micrometer emitter width

This paper presents details of the fabrication process and performance of an n-p-n silicon microwave bipolar transistor with emitter opening widths as small as 0.3 µm. The fabrication process involves local oxidation, ion implantation, and lateral etching techniques for emitter definition. Noise figure as low as 1.0 dB at 1.5 GHz, 2.0 dB at 4 GHz, and 3.3 d B at 6 GHz were achieved. Measured noise figures and -parameters are shown to be in approximate agreement with modeled performance based on device structure and process parameters. Prospects for further reductions in bipolar transistor noise figures are discussed.