Subnanosecond self-aligned I2L/MTL circuits

A self-aligned I
²
L/MTL technology featuring collectors doped from and contacted by polysilicon, self-aligned collector and base contact edges, and metal-interconnected bases is described. Experimental ring-oscillator circuits designed with 2.5-µm design rules and fabricated with this technology exhibit gate delays as small as 0.8 ns at
I_{c} = 100
µA for fan-in = 1 and fan-out = 3. Increased wiring flexibility and improved circuit density are inherent advantages of this self-aligned technology.