Vertical Diamond Schottky Barrier Diode Fabricated on Insulating Diamond Substrate Using Deep Etching Technique

Diamond Schottky barrier diodes (SBDs) with vertical channel structures are fabricated on an insulating diamond substrate. The deep etching technique is used to make a vertical channel structure in the diamond stacking layers of the p
⁺
/p
^-
/insulating substrate. Mo Schottky electrodes with the Al
₂
O
₃
field plate structure are also fabricated to realize a high breakdown voltage. As a result, I-V characteristics with a high forward current density >10
³
A/cm
²
and a high breakdown voltage >700 V are obtained at 25
^°
C and 250
^°
C. Baliga's figure of merit is 332 MW/cm
²
, which is equivalent to the high value previously reported for diamond SBDs with lateral channel or pseudovertical channel structures, and is also ten times higher than the limit of Si SBDs. High-power diamond SBDs are expected to be realized on a large area insulating diamond substrate using this technique.