Structural transition of Ge dots induced by submonolayer carbon on Ge wetting layer

We have investigated the influence of carbon on Ge dot growth on Si(100) su bstrates. To modify the Ge dot structure, submonolayers of carbon were depo sited on Ge wetting layers. The Ge deposited on the carbon-covered wetting layer tends to form dome structures instead of hut structures even at a sub strate temperature of 500 degrees C. The main effect of C is to enhance a s tructural transition from huts to domes by influencing the configurational energy of the Ge dots. The dominant factor to determine the dot size is the substrate temperature. Accordingly, small domes with 10-20 nm in diameter were formed by combining techniques of the submonolayer C on the Ge wetting layer and low-temperature deposition. (C) 2000 American Institute of Physi cs. [S0003-6951(00)03341-6].