The transistor was fabricated with 0.5-μm gate length and
300-μm gate width (30 fingers with 10-μm gate width per
finger). The lateral diffusion of n-well is around 0.2 μm, so the
effective gate length is about 0.3 μm. The I–V characteristics of
the transistor are shown in Fig. 2. The maximum available drain
current Ids is 150 mA at a Vgs of 3.5 V. An 11.6-V breakdown
voltage is obtained from varying the drain voltage while the
gate is fixed at 3.5 V, as is shown in the inset of Fig. 2. The
leakage current of the device is 14.5 pA/μm when Vds is 5 V
and Vgs is 0 V. Also, we obtained ON-state resistance from the
slope of the linear region of output characteristic curve with
maximum Vgs and a small Vds (0.1 V). The extracted value is
3.8 Ω · mm. To test the stability, the transistor was stressed on
maximum Vds and Vgs for 24 h. No obvious dc performance
degradation was observed.