Realization of linear integrated preamplifiers with low 1/f noise

Low 1/f noise direct coupled, dielectrically isolated linear integrated preamplifier circuits can be achieved through proper device and circuit design coupled with properly controlled fabrication technology. In accordance with theoretical considerations, PNP transistors were diffused in 100 orientation p-type dielectrically isolated material. Thin film resistors and aluminum metallization were utilized to complete the circuit. Rigorous control of heavy metal impurities in slice cleanup, diffusion furnaces, and metallization sources was maintained to improve noise performance. Adequate annealilng of the stressed dielectrically isolated structure was required. The post metallization annealing ambient was significant in reducing the 1/f noise resulting fr6m suface damage caused by the electron beam metallization source as well as other Process induced surface defects. The results of the various experiments will be discussed.