What is strained silicon semiconductor?

Strained silicon is a layer of silicon in which the silicon atoms are stretched beyond their normal interatomic distance. This can be accomplished by putting the layer of silicon over a substrate of silicon germanium (SiGe).

What is the purpose of strained silicon?

A technique that deposits silicon (Si) on top of silicon germanium (SiGe) for making transistors on a chip. In so doing, the silicon atoms are stretched (“strained”) to line up with the silicon germanium atoms, which are wider apart. This causes less resistance in the silicon and increases performance.

Why are Mosfet intentionally strained?

When the MOSFET is strained, the energy bands split, with the “out-of-plane” ellipsoids having lower energy. The electrons move from the high energy “in-plane” ellipsoids (with the poor effective mass) to the low energy “out-of-plane” ellipsoids (with the good effective mass).

What is a power MOSFET used for?

A type of metal oxide semiconductor field effect transistor (MOSFET) used to switch large amounts of current. Power MOSFETs use a vertical structure with source and drain terminals at opposite sides of the chip. The vertical orientation eliminates crowding at the gate and offers larger channel widths.

What is the primary motivation for replacing planar MOSFET with Finfets?

To improve gate control over the channel and reduce threshold voltage roll-off.

What causes a MOSFET to fail?

If the maximum operating voltage of a MOSFET is exceeded, it goes into Avalanche breakdown. If the energy contained in the transient over-voltage is above the rated Avalanche energy level, then the MOSFET will fail. The device fails short circuit, initially, with no externally visible signs.

How is FinFET better than Mosfet?

FinFETs block short-channel effects better than planar MOSFETs, enabling transistor scaling. The planar design doesn’t scale well beyond gate lengths of 30 nm. The gate oxide stops sealing-in the gate control on the source, and the drain is weak.


The FinFET devices have significantly faster switching times and higher current density than planar CMOS (complementary metal-oxide-semiconductor) technology. FinFET is a type of non-planar transistor, or “3D” transistor. It is the basis for modern nanoelectronic semiconductor device fabrication.

What happens if MOSFET fails?

When MOSFETS fail they often go short-circuit drain-to-gate. This can put the drain voltage back onto the gate where of course it feeds (via the gate resistors) into the drive circuitry, possibly blowing that section. It will also get to any other paralleled MosFet gates, blowing them also.

Where are power MOSFETs used?

Power MOSFETs are widely used in transportation technology, which include a wide range of vehicles. In the automotive industry, power MOSFETs are widely used in automotive electronics. Power MOSFETs (including DMOS, LDMOS and VMOS) are commonly used for a wide range of other applications.

What are the benefits of strained silicon transistors?

Moving these silicon atoms farther apart reduces the atomic forces that interfere with the movement of electrons through the transistors and thus better mobility, resulting in better chip performance and lower energy consumption. These electrons can move 70% faster allowing strained silicon transistors to switch 35% faster.

How does strain affect the mobility of a pFET?

The strain changes the lattice constant of the silicon crystal and therefore the E–krelationship through the Schrodinger’s wave equation. The E–krelationship, in turn, determines the effective mass and the mobility. For example, the hole surface mobility of a PFET can be raised when the channel is compressively stressed.

What are the opportunities for scaling of MOSFETs?

Special emphasis is placed on the understanding of the opportunities for future MOSFET scaling including mobility enhancement, high-kdielectric and metal gate, SOI, multigate MOSFET, metal source/drain, etc. Device simulation and MOSFET compact model for circuit simulation are also introduced.

Why is power consumption of MOSFET so low?

Thanks to the reduction in Cand V dd, power consumption per chip has increased only modestly per node in spite of the rise in switching frequency, fand the doubling of transistor count per chip at each technology node.