A comparison between fast power diodes fabricated on substrates made by silicon to silicon direct bonding and on epitaxial substrates

Fast p⁺ n^-n⁺ and self adjusting p ⁺ emitter efficiency diodes (SPEED) were fabricated on n⁺ n^- silicon to silicon direct bonded (SDB) substrate material and compared to diodes simultaneously processed on epitaxially grown substrates. The experimental data of reverse recovery time and forward voltage drop of the SDB diodes revealed to be better than those of epitaxial diodes. High energy proton implantation (2.5 MeV) was used to adjust the switching behaviour of pin diodes. The dependence of switching behaviour and current-voltage (I-V) characteristics on proton implantation dose was investigated for p⁺ n^-n⁺ and SPEED diodes. SPEED diodes with an on-voltage comparable to p⁺ n^-n⁺ diodes exhibited smaller reverse recovery time and maximum reverse current values than those. A soft factor of 1.5 of SPEED diodes is combined with a maximum reverse voltage 20% lower than for p⁺ n^-n⁺ diodes. Diodes with reverse recovery times as low as 70 ns were fabricated showing forward voltage drops less than 5.2 V at a forward current of 140 A (10 mm² area)