Study on the Al/silicon rich oxide/Si structure as a surge suppresser

Abstract

Summary form only given. The off-stoichiometry silicon oxide, or silicon rich oxide (SRO), also known as semi-insulating polysilicon (SIPOS), is a material formed by SiO/sub 2/ with excess Si (Dong et al, J. Electrochem. Soc. vol. 125, no. 5, p. 819, 1978). This material is normally obtained by CVD with silane and nitrous oxide as the reactive gases. In modern IC technology, input (or output) ESD protection is a major limitation to further increases in circuit integration. The two main effects are the large area consumption, and the high frequency limitation imposed by the input cell size needed for this application. One possible solution to this problem is that the input pad by itself behaves as an input protection. To achieve this function, the input pad must be able to provide a conduction path to the substrate for low frequency voltages above a given value, and also must be able to handle the very high frequency characteristics of the ESD transients. The I-V characteristics of Al-SRO-Si suggest the possibility of using this device as a surge suppresser, and it may be possible to substitute an input pad for a device that does not use more area than a simple pad. This paper presents a study of the I-V relationship of the Al-SRO-Si structure from low to medium frequencies and under the human body model spike generator. It is shown that this device may be used as a low frequency surge suppresser and that more work must be done to determine whether it can be used as an input protection for ICs.