Delta Doped beta-Ga2O3 Field Effect Transistors With Regrown Ohmic Contacts

We report silicon delta-doped beta-Ga2O3 metal semiconductor field effect transistors (MESFETs) with source-drain ohmic contacts formed by patterned regrowth of n-type Ga2O3. We show that regrown n-type contacts can enable a lateral low-resistance contact to the two-dimensional electron gas channel, with contact resistance lower than 1.5 Omega-mm. The fabricated MESFET has a peak drain current (I-D,I-MAX) of 140 mA/mm, transconductance (g(m)) of 34 mS/mm, and 3-terminal off-state breakdown voltage of 170 V. The proposed device structure could provide a promising path towards vertically scaled beta-Ga2O3 field effect transistors.