Investigation on Self-Adjust Conductivity Modulation SOI-LIGBT Structure (SCM-LIGBT) for Monolithic High-Voltage IC

A novel composite device structure named self-adjust conductivity modulation lateral insulated gate bipolar transistor (SCM-LIGBT), including normal LIGBT region (NLT region), the EM-nMOS region (ENM region), and the series diode region (DIO region), is proposed in this paper. By adding the enhanced-mode nMOS region and the series diodes region, the parasitic NPN transistor (NPN) bipolar structure in the normal LIGBT structure can be triggered in on-state and the conductivity modulation is dramatically enhanced, which leads to the improvement on the current capability and the forward voltage. In addition, due to the base voltage of the parasitic NPN bipolar structure in the proposed device can be clamped at the forward threshold of the series diodes, therefore the latch-up issues can be immunized to guarantee the forward-biased safe operating area. Numerous simulations and measurements are presented to investigate the electrical characteristics of the proposed structure. The length of the fabrication SCMLIGBT is 78.5 μm, and the width of the DIO and NLT is 830 μm, while the width of the ENM is 4100 μm. The results demonstrate that the proposed SCM-LIGBT achieves a highcurrent capability (J
_A
) of 2428 A/cm
²
at V
_G
= 10 V, a low on-state voltage drop of 1.15 V at J
_A
= 150 A/cm
₂
with its breakdown voltage of 590 V.