AVS 46th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM2-ThA

Paper EM2-ThA10
A New Approach for the Fabrication of Device-Quality Ge/GeO@sub 2@/SiO@sub 2@ Interfaces Using Low Temperature Remote Plasma Processing

Thursday, October 28, 1999, 5:00 pm, Room 611

Session: Silicon Carbide and Dielectrics on Si
Presenter: R.S. Johnson, North Carolina State University
Authors: R.S. Johnson, North Carolina State University
H. Niimi, North Carolina State University
G. Lucovsky, North Carolina State University
Correspondent: Click to Email
It has been shown that low temperature (300°C) remote plasma enhanced processing can separately and independently control interface formation and bulk oxide deposition on silicon substrates. Plasma processing is followed by a low thermal budget thermal anneal, e.g., 30 s at 900°C. This process has been used for the formation of the device-quality gate dielectrics in both NMOS and PMOS devices. In the new results reported in this paper, this process has been modified and applied to germanium substrates to determine if it can provide a successful pathway to device-quality Ge-dielectric interfaces. The new process is similar low temperature (300°C) three-step process consisting of (i) an O@sub 2@/He plasma-assisted oxidation of the Ge surface to form a superficial germanium-oxide passivating film, (ii) deposition of a SiO@sub 2@ bulk film by remote plasma-enhanced CVD from SiH@sub 4@ and O@sub 2@, and (iii) a post-oxide deposition anneal for chemical and structural relaxation. We track the initial stages of the plasma-assisted oxidation of the germanium substrate using on-line Auger Electron Spectroscopy (AES). We then discuss why the O@sub 2@ /He plasma oxidation is critical for prevention of "subcutaneous" oxidation of GeO@sub 2@ -Ge interface during the deposition step. As in the case of Si deives, the oxidation step is required for formation of a device quality interface.