Dae-Seok Byeon

A fast-switching SOI SA-LIGBT without NDR region

The SOI separated shorted-anode LIGBT (SSA-LIGBT) has been investigated by experiments and numerical device simulations. In order to suppresses the negative differential resistance regime which is the inherent drawback of the shorted anode LIGBT (SA-LIGBT), the SSA-LIGBT increases the pinch resistance by employing the highly resistive n-drift region as an electron conduction path. The SSA-LIGBT shows a remarkably decreased on-state voltage drop when compared with the conventional SA-LIGBT and shows a one-order faster turn-off time than that of the LIGBT.

A new gradual hole injection dual-gate LIGBT

A new shorted-anode lateral insulated gate bipolar transistor (SA-LIGBT), entitled gradual hole injection dual gate LIGBT (GHI-LIGBT), is proposed and fabricated. The new device employs a dual gate and p/sup +/ injector in order to initiate the hole injection gradually from the anode electrode into the drift region so that the negative differential resistance (NDR) regime may be eliminated. The experimental results show that the NDR regime, which may cause undesirable device characteristics, is completely eliminated in the GHI-LIGBT, and the forward voltage drop is reduced by 1 V at the current density of 200 A/cm/sup 2/ in comparison with the conventional SA-LIGBT.A new shorted-anode lateral insulated gate bipolar transistor (SA-LIGBT), entitled gradual hole injection dual gate LIGBT (GHI-LIGBT), is proposed and fabricated. The new device employs a dual gate and p/sup +/ injector in order to initiate the hole injection gradually from the anode electrode into the drift region so that the negative differential resistance (NDR) regime may be eliminated. The experimental results show that the NDR regime, which may cause undesirable device characteristics, is completely eliminated in the GHI-LIGBT, and the forward voltage drop is reduced by 1 V at the current density of 200 A/cm/sup 2/ in comparison with the conventional SA-LIGBT.

Optimum design of the field plate in the cylindrical p+n junction: analytical approach

Analysis of the breakdown voltage in the p+n junction with the field plate is presented for an optimum design. The breakdown voltage is analyzed by employing the approximated electric field and breakdown path in terms of the field plate parameters and the applied reverse bias. The optimum values for oxide thickness and the field plate width are derived by the use of the breakdown voltage. The calculated breakdown voltages agree well with the experimental data and two-dimensional numerical simulation result.

CB-BRT: a new base resistance-controlled thyristor employing a self-aligned corrugated p-base

We propose and fabricate a new base resistance-controlled thyristor (BKT) employing a self-aligned corrugated p-base. The new device, entitled CB-BRT, suppresses the snap-back effectively and increases the maximum controllable current. Experimental results show that the snap-back of the CB-BRT is reduced significantly when compared with that of the conventional BRT. Also, the maximum controllable current of the CB-BRT increases as compared with the conventional BRT.We propose and fabricate a new base resistance-controlled thyristor (BKT) employing a self-aligned corrugated p-base. The new device, entitled CB-BRT, suppresses the snap-back effectively and increases the maximum controllable current. Experimental results show that the snap-back of the CB-BRT is reduced significantly when compared with that of the conventional BRT. Also, the maximum controllable current of the CB-BRT increases as compared with the conventional BRT.

ANALYTICAL SOLUTION OF THE BREAKDOWN VOLTAGE FOR 6H-SILICON CARBIDE P+N JUNCTION

An analytical solution of the breakdown voltage for 6H‐silicon carbide p+n junction has been derived by employing an effective ionization coefficient. The breakdown voltage extracted from our analytical model agrees fairly well with the experimental data in the range of 1016–1018 cm−3 doping levels.

The separated shorted-anode insulated gate bipolar transistor with the suppressed negative differential resistance regime

The separated shorted-anode LIGBT (SSA-LIGBT), which suppresses effectively the negative differential resistance regime, is investigated by performing 2-dimensional numerical simulation. In order to suppress the negative differential resistance regime, the SSA-LIGBT increases the pinch resistance by employing the highly resistive n-drift region as an electron conduction path instead of the lowly resistive n buffer region of the conventional SA-LIGBT. The SSA-LIGBT shows the remarkably decreased forward voltage drop when compared with the conventional SA-LIGBT and shows the one-order faster turn-off time than that of the LIGBT.

An insulated gate bipolar transistor employing the plugged n+ anode

A vertical Insulated Gate Bipolar Transistor, entitled CB-IGBT(Carrier-inducing Barrier-controlled IGBT) has been proposed and verified by a two-dimensional numerical simulation. The structure of the proposed device is almost identical with that of the conventional IGBT, except for the anode structure in which the p-barrier region and n+ anode region are employed. In the CB-IGBT, the potential barrier height at the junction between the p-barrier region and n-drift region is controlled by the amount of carriers, so that the trade-off relation between the on-state voltage drop and the switching speed is decoupled efficiently. The switching speed of CB-IGBT is so much enhanced with a negligible increase of the on-state voltage drop, since electrons stored in the n-drift region can be extracted rapidly into the n+ anode via p-barrier region during turn-off process.

The Closed-Form Solutions For The Breakdown Voltages Of 6H-SiC Reachthrough Diodes

The closed-form analytic solutions for the breakdown voltage of 6H-SiC RTD, reachthrough diode, having the structure of p + -n - n + , are successfully derived by solving the impact ionization integral using effective ionization coefficient in the reachthrough condition. In the region of the lowly doped epitaxial layer, the breakdown voltages of 6H-SiC RTD nearly constant with the increased doping concentration. Also the breakdown voltages of 6H-SiC RTD decrease, in the region of the highly doped epitaxial layer, which coincides with Baligaseq. [1].

A base resistance controlled thyristor with the self-align corrugated p-base

A new base resistance controlled thyristor with the self-aligned corrugated p-base, entitled CB-BRT, is proposed and fabricated in order to suppress the snapback phenomenon and to increase the maximum controllable current. The corrugated p-base is formed by self-aligned boron diffusion using the gate polysilicon as a mask. The new device reduces the snapback effectively by decreasing the latching current without sacrificing the forward voltage. The regenerative thyristor action is suppressed during the turn-off period so that the maximum controllable current increases in the CB-BRT.

The breakdown voltage of negative curvatured p+n diodes using a SOI layer

Abstract The negative curvatured p+n diode (NCD) is fabricated on direct bonded SOI wafer and the breakdown characteristics are investigated. The breakdown voltage of the NCD is larger than that of an ideal parallel-plane p+n diode. The calculated electric field of the NCD supports the experimental results of 220 V higher than that (156 V) of the parallel-plane p+n diode.