The buried oxide properties in oxygen plasma-enhanced low-temperature wafer bonding

We have studied the buried oxide integrity in oxygen plasma-enhanced low-te mperature wafer bonding. As observed by cross-sectional scanning electron m icroscopy, the bonding strength of the oxygen plasma-treated sample is so l arge that forced separation for a 600 degrees 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 goo d structure property with negligible defects as observed by cross-sectional transmission electron microscopy. From capacitance-voltage measurement, go od electrical property is evidenced by the low oxide-charge and interface-t rap densities of -2.0 x 10(10) cm(-2) and 3 x 10(10) eV(-1) cm(-2), respect ively, from capacitance-voltage measurements. (C) 2000 The Electrochemical Society. S0013-4651(99)11-083-8. All rights reserved.