Justify the statement. IGBT uses a vertically oriented structure.

Question

Justify the statements.

1. IGBT uses a vertically oriented structure.

2. IGBT is preferred as a power switch over both power BJT and MOSFET.

3. Punch through IGBT structure are more popular and are widely used.

Answer 1

1. IGBT uses vertically oriented structure.

IGBT use vertically oriented structure to reduce the resistance and to increase the current flow area.

Hence IGBT uses vertically oriented structure.

2. IGBT is preferred as a power switch over both power BJT and MOSFET.

IGBT combines the qualities of BJT and MOSFET. The high switching speed of MOSFET and low conduction losses of BJT. Also, IGBT have low on-state losses as compared to BJT and MOSFET. IGBT have high input impedance. IGBT is a voltage controlled device, so the drive circuit of IGBT is simple. The current rating and voltage rating of IGBT is better as compare to BJT and MOSFET. The turn off time of IGBT is greater than MOSFET. Bipolar Junction transistor (BJT) have the second breakdown problem, but IGBT do not have second breakdown problem. So, IGBT combines the advantages of BJT and MOSFET hence, IGBT is preferred as a power switch over both BJT and MOSFET.

3. Punch through IGBT structure are more popular and are widely used.

Punch through IGBT have n+ buffer layer. In punch through IGBT the n+ buffer layer is in between n- and p+ layer. This n+ layer is for increasing the blocking voltage. Punch through IGBT have faster turn off. The on state losses will be less in punch through IGBT because of small n- drift region. Punch through IGBT is suitable for DC circuit applications. Hence punch through IGBT structure are more popular and are widely used.