Building in Reliability Through a 100x Reduction in Mobile Ions in a 0.8 μm BiCMOS Process

Abstract

AbstractThe reduction of mobile ions--mainly Na+, but also K+, H+ and Li+, is very critical as our gate oxide thickness and Leff decreases. Hot electron induced hydrogen compensation of boron doped silicon changes the PMOS Leff and NPN BVebo. This paper shows how to reduce Na+ by 100X, through the use of Triangular Voltage Sweep (TVS). This paper is designed to give scientists and engineers a case history where we reduced these levels from 1012 to 1010 mobile ions/cm2 in our 0.8μm BiCMOS process. This was accomplished by adding Ammonium Fluoride mixture dips at appropriate steps. For fast feedback, we can non-destructively measure Na, K, and H within 10 minutes of completing phororesist removal at any of the metallization steps using TVS. In addition to BiCMOS, TVS measure is a power tool in Nonvolatile Memories for predicting in-line data retention, when data retention is associated with charge gain.