A Depletion-Load, p-Channel, Bipolar-IGFET Technology

Since the development of the low-threshold ( 7 r = -- 1 volt) metalgate p-channel Al 2 0 3 -Si02 I G F E T technology, 1 further technological advances have been made to improve circuit speed and interface flexibility of I G F E T circuits. Two significant improvements have been the incorporation of bipolar-iGFET (BIGFET) 2 devices on the same monolithic silicon-integrated circuit (sic) and the application of ion implantation to fabricate depletion-load IGFET'S. 3 These have resulted in an I G F E T technology whose circuits are completely compatible with the standard 5-volt bipolar TTL family in terms of input and output levels as well as power supply. Furthermore, the relatively high functional packing density of the I G F E T technology makes it an extremely attractive option in M S I / L S I applications. These have been successfully realized in the design and fabrication of several Bell System catalog and custom circuits. In this paper, the technology characteristics of the depletion-load B I G F E T technology are described.