Structural defect-free GaPN and InGaPN layers were grown on a Si (100) substrate. Light emitting diodes (LEDs) and Si metaloxide-semiconductor field effect transistors (MOSFETs), which are elemental devices for optoelectronic integrated circuits(OEICs), were monolithically integrated in a single chip with a Si layer and an InGaPN/GaPN double hetereostructure layer grown on a Si substrate. The developed process flow was based on a conventional MOSFET process flow. It was confirmed that light emission from the LED was modulated by switching the MOSFET. The growth and fabrication process technologies are effective in the realization of monolithic OEICs.