Lateral emitter-controlled thyristor (LECT) on SOI

Summary form only given. A new lateral power device on SOI called the lateral emitter controlled thyristor (LECT) is proposed, and simulation results are presented. The LECT has better forward voltage drop (V/sub F/), larger forward biased safe operating area (FBSOA) and reverse biased safe operating area (RBSOA) than the lateral IGBT (LIGBT). LECT implementation on a thin SOI layer is suitable for smart power IC applications. The device is composed of a lateral gate-controlled PNPN thyristor in series with a short channel lateral double-diffusion MOSFET (LDMOS). The gate of the LDMOS is tied together with the turn-on gate of the thyristor to form a single control gate. A P-channel MOSFET (PMOS) is formed between the P base of the thyristor and the P-body of LDMOS, and the PMOS gate is tied to the LECT cathode. Two-dimensional simulations with MEDICI were carried out for a 300 V LECT structure to verify its operation. The forward voltage drop of the LECT and of a similar LIGBT are compared for two gate voltages. Compared at 100 A/cm/sup 2/, the V/sub F/ of the LECT is 0.4 V less than that of the LIGBT at V/sub g/=15 V, and 1 V less at V/sub g/=10 V. The results clearly show that the LECT has three distinct operating regions: a thyristor-like forward conduction region, a high voltage current saturation region, and a third region at high voltage/high current before it reaches its FBSOA point. The LECT has a much larger FBSOA than the LIGBT. This paper presents a detailed analysis of the mechanism for current saturation and the factors that determine the FBSOA and the RBSOA of the LECT.