ESD-testing and models

In the 60-ties a very high vulnerability of the new discrete MOS-components was realised. They failed often without any apparent reason. A thorough failure analysis of damaged components started to settle failure mechanisms. This led to the understanding that electrostatic discharges caused voltage breakdown in the thin silicon gate oxide of the MOS-circuits. The accidents happened during the handling of the circuits. The operators had been charged triboelectrically and by touching some pin of the circuit a discharge destroyed it. The thickness of the oxides was normally about 1000 Å, corresponding to a breakdown voltage 100V. The failure mode was often a short circuit between gate and source or drain. About 50% of all failures were caused by ESD.