We study the electron transport through silicon serial triple quantum dots (TQDs) formed effectively in a lithographically-defined multiple quantum dot system on a silicon-on-insulator substrate at a temperature of 4.2 K. Our serial TQDs are composed of two lithographically-patterned QDs and another one in between formed by stress during the pattern-dependent oxidation process. The TQDs formation is confirmed by equivalent circuit simulations, which show an excellent agreement with the experimental results. With detailed analysis of the charge configurations in the TQDs, we discuss the distinct properties of the TQDs, including electron transport at the charge quadruple points. In addition, we discuss higher order tunneling processes of the TQDs. The analysis of electron states in the silicon TQDs is a crucial step toward the future implementation of integrated silicon quantum information devices. (C) 2009 Elsevier Ltd. All rights reserved.