Hammocks versus hammock

This paper analyses a particular reliability scheme known as hammock networks. These seem to be a very good fit for arrays of FinFET transistors (but also segmented bulk MOSFET, vertical FET, vertical slit FET, gate-all-around FET), as well as arrays of beyond CMOS devices. In particular, our aim is to study compositions of such networks. By composition of two hammock networks we mean a hammock network where the transistors/switches themselves are replaced by hammock networks (of transistors/switches). In order to study such compositions we start from fresh results computing exactly the reliability polynomials associated to small hammock networks. We use these results to compute exactly the reliability polynomials associated to compositions (of hammock networks). Finally, compositions of hammock networks are compared with a (square) hammock network of the same size (i.e., number of transistors/switches), while also accounting for the number of wires. Analyzing the results reveals that compositions of hammocks present interesting symmetries, and, while they do come close to the reliability of a single (square) hammock network, they are always slightly lagging behind.