High speed integrated injection logic (I/sup 2/L)

High speed integrated injection logic (I/SUP 2/L) circuits can be manufactured in a process using oxide separation involving a very thin epitaxial layer and ion implantation. Electronic improvements which decrease the charge storage in both the p-n-p and n-p-n transistor are discussed. Analytic expressions are derived which show the consequences for the minority charge stored in the base of the n-p-n transistor and for the influences on the current noise margin. A tradeoff between noise margin and speed is then made. Besides the reduction in delay time, another attractive aspect of this approach is that it allows a simple layout design. By using separate p-n-p and n-p-n transistors, the position of the n-p-n transistors can be adapted to the logic wiring because there is no limitation in the number of crossovers. Some experimental results are given. A minimum value of the propagation delay time of 3 ns has been measured.