Transparent Amorphous Ru–Si–O Schottky Contacts to In–Ga–Zn–O

Transparent amorphous oxide semiconductors (TAOSs), such as In-Ga-Zn-O (a-IGZO), are the subject of intensive experimental and theoretical research aimed at applications in transparent electronics. With the development of novel device applications came an increased demand for the understanding and control of a-IGZO Schottky contact properties. Rectifying contacts are suitable for the development of Schottky diodes and metal-semiconductor field-effect transistors (MESFETs) for fast and low power consumption integrated circuits and active-matrix displays. We propose fabrication of Schottky barrier to a-IGZO based on transparent conductive oxide (TCO), namely Ru-Si-O. We have found that atomic composition and microstructure of this TCO are effective in preventing interfacial reactions in the contact region which allows to avoid pre-treatment of the semiconductor surface. Ru-Si-O Schottky contacts to a-IGZO have been fabricated by means of reactive sputter-deposition. We provide comprehensive results on effects of Ru-Si-O chemical composition on properties of rectifying contacts to a-IGZO. Depending on oxygen content in Ru-Si-O sputtering atmosphere, for a specific process window (from 10% to 20% of O2 in sputtering atmosphere), highly rectifying transparent Schottky barriers are obtained without additional a-IGZO surface treatment.