Investigations on Al/Si interface

Abstract

Aluminium and aluminium alloys are widely used as interconnecting materials in silicon integrated circuits. The processing technique includes vacuum deposition and—after patterning— heat treatment of the metal film. The heat treatment of aluminium metallization is accompanied by the dissolution of the underlying silicon into the metal and the consequent penetration of aluminium into the silicon. The dissolution process is highly nonuniform on the contact surface creating crystallographic etch pits, which can cause excessive leakage or even shorting of thep-n junction. Furthermore, silicon precipitation in the contact windows that occurred on cooling down can cause increased contact resistance.

We intend to present surface analytical investigations and electrical measurements on the Al/Si interface in case of pure and silicon-alloyed aluminium metallization. The results show the effect of various postmetallization heat treatments on the Al/Si contact.