Room Temperature Bonding of CVD Polycrystalline Diamond Wafers to Semiconductor and Piezo-electric Single Crystalline Wafers

To achieve the room temperature bonding of CVD polycrystalline diamond wafers to other semiconductor or piezoelectric single crystalline wafers, plasma assisted polishing (PAP) combined with gas cluster ion beam (GCIB) irradiation was firstly proposed to polish diamond wafers. Using this new polishing method, the peak-to-valley (Pv) value and root-mean-square (RMS) surface roughness of 2-inch polycrystalline diamond wafers were controlled to within 3 µm and 1 nm, respectively. The polished 2 inch diamond wafers were for the first time successfully bonded to 4 inch LiNbO
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and 2 inch GaN wafers at room temperature using surface activated bonding (SAB) with Si nano-adhesion layer.