Room temperature oxidation of Cu3Ge and Cu-3(Si1-xGex) on Si1-xGex

Room temperature oxidation of CU3 (Si1-chiGechi) and Cu3Ge films grown on S i1-chiGechi at a temperature of 200-400 degreesC was studied using transmis sion electron microscopy (TEM) in conjunction with energy dispersive spectr ometry (EDS). For Cu-3(Si1-chiGechi) and Cu3Ge films grown at 200 degreesC and then exposed to air, room temperature oxidation occurred. The Cu3Ge fil m was superior to the Cu-3(Si1-chiGechi) film in reducing the oxidation rat e because of its higher Ge concentration. Annealing at higher temperatures such as 400 degreesC resulted in Ge segregation out of the Cu-3(Si1-chiGech i) film or Si diffusion from the Si1-chiGechi substrate into the Cu3Ge over layer, and hence enhanced the oxidation rate of Cu-3(Si1-chiGechi) and Cu3G e films. The present study shows that upon exposure to air even the Cu3Ge f ilm grown on Si1-chiGechi is subject to room-temperature oxidation, reveali ng that the use of Cu3Ge contacts on Si1-chiGechi may be limited by some st rict conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.