The Buried Oxide Properties in Oxygen Plasma-Enhanced Low-Temperature Wafer Bonding

Abstract

We have studied the buried oxide integrity in oxygen plasma-enhanced low-temperature wafer bonding. As observed by cross-sectional scanning electron microscopy, the bonding strength of the oxygen plasma-treated sample is so large that forced separation for a 600 °C bonded wafer takes place at the heterointerface of the thermal oxide and the Si substrate rather than at the oxide-oxide bonding interface. The plasma-enhanced bonding shows good structure property with negligible defects as observed by cross-sectional transmission electron microscopy. From capacitance-voltage measurement, good electrical property is evidenced by the low oxide-charge and interface-trap densities of -2.0×1010cm-2and 3×1010eV-1cm-2, respectively, from capacitance-voltage measurements.