Monolithic integrated circuit for tuning TV receiver - has various zones for bipolar transistor and MOS triode or tetrode formed simultaneously to reduce mfg. stages

摘要

The integrated circuit uses bipolar semiconductors and MOS semiconductor elements. It uses a double epitaxial layer with the collector zone for the bipolar transistor formed in conjunction with one of the two protective diodes for the MOS element, the other of which is formed in conjunction with the base terminal for the bipolar transistor. The source and drain of the MOS element are formed together with the emitter of the bipolar transistor. The base zone of the bipolar transistor is formed before gate oxidisation or between two gate oxidisation stages for limit frequencies above 2GHz. The gate oxide layer also provides the masking layer for the base zone of the bipolar transistor for emitter diffusion or implantation. Pref. the metallisation for the semiconductors comprises Al with between 0.5 an 2 percent Si, or a multilayer metallisation using Ti, Pt and Acc or refined Al. Resistors and capacitors can also be formed at the same time as the bipolar transistors and the MOS elements.