The advanced improvement of PN mesa junction diode prepared by silicon-wafer direct bonding

The key processes of Silicon-Wafer Direct Bonding (SDB), hydrophilic surface formation and optimum two-step heat treatment have been developed. However, there are still many unknown factors, such as native oxide, defects etc., influencing the characteristics of the bonded interface of Si/Si. The additional wafer treatment in diluted HF solution after hydrophilic surface formation can not only etch off native oxide but also form hydrophilic surface, and provide a voidless Si/Si bonding interface. The electrical characteristics of both N⁺ /P and N/P junction mesa diodes prepared by this novel SDB process were examined. Both of them have excellent electrical characteristics and their breakdown voltages are all over 280 V