Vertical Ga2O3 MOSFET With Magnesium Diffused Current Blocking Layer

Vertical MOSFET is a critical milestone in the gallium oxide (Ga
₂
O
₃
) roadmap. However, the lack of an effective current blocking layer in Ga
₂
O
₃
, which is essential for any DMOS-like (double-diffused MOSFET) transistors has proved to be the main barrier to the achievement of a vertical MOSFET. Here, we report two novel findings -first, a selective diffusion doping technique utilizing magnesium (Mg) doping spin-on-glass (SOG) as a dopant source to form a current blocking layer (CBL), and second, the first demonstration of a vertical Ga
₂
O
₃
MOSFET with the Mg diffused CBL- Vertical Diffused Barrier Field-Effect-Transistor (VDBFET). The device exhibits an excellent field-effect-transistor (FET) behavior with a high on-off ratio of 10
⁹
and a decent saturation. Due to the unique nature of the Mg-doped region, the transistor is normally-off with a turn-on voltage of ~7 V. An on-current of 0.15 kA/cm
²
is measured with a gate voltage (
${V}_{g}$
) of 12 V, and a drain voltage (
${V}_{d}$
) of 15 V. The three terminal breakdown voltage measured at a
${V}_{g}$
of 0V is 72 V. The successful demonstration of the first Ga
₂
O
₃
VDBFET significantly brightens the prospect for its application in high power electronics.