Research and development Power semiconductor device

1 research , development

1.1 packaging
1.2 improvement of structures
1.3 wide band-gap semiconductors

research , development
packaging

the role of packaging to:

connect die external circuit.
provide way remove heat generated device.
protect die external environment (moisture, dust, etc.).

many of reliability issues of power device either related excessive temperature or fatigue due thermal cycling. research carried out on following topics:

cooling performance.
resistance thermal cycling closely matching coefficient of thermal expansion of packaging of silicon.
the maximum operating temperature of packaging material.

research ongoing on electrical issues such reducing parasitic inductance of packaging; inductance limits operating frequency, because generates losses during commutation.

a low-voltage mosfet limited parasitic resistance of package, intrinsic on-state resistance low 1 or 2 milliohms.

some of common type of power semiconductor packages include to-220, to-247, to-262, to-3, dpak, etc.

improvement of structures

the igbt design still under development , can expected provide increases in operating voltages. @ high-power end of range, mos-controlled thyristor promising device. achieving major improvement on conventional mosfet structure employing super junction charge-balance principle: essentially, allows thick drift region of power mosfet heavily doped, thereby reducing electrical resistance electron flow without compromising breakdown voltage. juxtaposed region doped opposite carrier polarity (holes); these 2 similar, oppositely doped regions cancel out mobile charge , develop depleted region supports high voltage during off-state. on other hand, during on-state, higher doping of drift region allows easy flow of carriers, thereby reducing on-resistance. commercial devices, based on super junction principle, have been developed companies infineon (coolmos products) , international rectifier (ir).

wide band-gap semiconductors

the major breakthrough in power semiconductor devices expected replacement of silicon wide band-gap semiconductor. @ moment, silicon carbide (sic) considered promising. sic schottky diode breakdown voltage of 1200 v commercially available, 1200 v jfet. both majority carrier devices, can operate @ high speed. bipolar device being developed higher voltages (up 20 kv). among advantages, silicon carbide can operate @ higher temperature (up 400 °c) , has lower thermal resistance silicon, allowing better cooling.