Enhancement-Mode AlN/GaN MOSHFETs on Si Substrate With Regrown Source/Drain by MOCVD

High-performance enhancement-mode (E-mode) AlN/GaN metal-oxide-semiconductor heterojunction field-effect transistors (MOSHFETs) on Si substrates have been demonstrated. Record high peak transconductance G
_m
of 509 mS/mm and maximum drain current I
_d
of 860 mA/mm were achieved for E-mode MOSHFETs with a source/drain spacing value L
_sd
of 0.7 m. Low gate leakage current (<;10
^-3
mA/mm) and improved ohmic contact resistance (0.153 Ω·mm) were enabled by a combination of Al
₂
O
₃
gate dielectric and regrown source/drain contacts. Al
₂
O
₃
also significantly increases the 2DEG density under the channel, which is beneficial for device performance by reducing the access resistance. The on-resistance is as low as 1.63 mm. The average regrowth interface resistance across the sample was estimated to be 0.056 Ω·mm. The E-mode MOSHFETs exhibit a high I
_on
/I
_off
ratio up to 10
⁶
.