Recent observations of macroscopic quantum condensation using electron and hole (e-h) bilayers in condensed matter activate the research of its application to electronics. However, no attempts have so far been made to observe the condensation in Si, the most important material in electronics, due to the lack of the technology for forming closely-packed e-h bilayers. Here we propose and experimentally demonstrate the method to form the e-h bilayer at the interface of Si metal-oxide-semiconductor transistors.