Vertical Ga2O3 MOSFET With Magnesium Diffused Current Blocking Layer

Vertical MOSFET is a critical milestone in the gallium oxide (Ga2O3) roadmap. However, the lack of an effective current blocking layer in Ga2O3, 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 utilizingmagnesium (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 Ga2O3 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 109 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 similar to 7 V. An on-current of 0.15 kA/cm(2) is measuredwith a gate voltage (V-g) of 12 V, and a drain voltage (V-d) of 15V. The three terminal breakdownvoltagemeasured at a V-g of 0V is 72 V. The successful demonstration of the first Ga2O3 VDBFET significantly brightens the prospect for its application in high power electronics.

Automated summary

The lack of an effective current blocking layer in Ga2O3 has been a major barrier to achieving a vertical MOSFET. However, a selective diffusion doping technique utilizing magnesium-doped spin-on-glass has been used to form a current blocking layer, leading to the successful demonstration of a vertical Ga2O3 MOSFET for the first time.