AN-9010 Datasheet, PDF (1/17 Pages) Fairchild Semiconductor – MOSFET Basics

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AN-9010
MOSFET Basics
Summary
The Bipolar Power Transistor (BPT), as a switching device
for power applications, had a few disadvantages. This led to
the development of the power Metal Oxide Semiconductor
Field Effect Transistor (MOSFET). The power MOSFET is
used in applications such as Switched Mode Power Supplies
(SMPS), computer peripherals, automotive, and motor
control. Continuous research has improved its
characteristics for replacing the BJT. This application note
is a general description of power MOSFETs and a
presentation of some of Fairchild’s product specifications.
History
The theory behind the Field Effect Transistor (FET) has
been known since 1920~1930, which is 20 years before the
bipolar junction transistor was invented. At that time, J.E.
Lilienfeld of the USA suggested a transistor model having
two metal contacts on each side with a metallic plate
(aluminum) on top of the semiconductor. The electric field
at the semiconductor surface, formed by the voltage
supplied at the metallic plate, enables the control of the
current flow between the metal contacts. This was the initial
concept of the FET. Due to lack of appropriate
semiconductor materials and immature technology,
development was very slow. William Shockely introduced
Junction Field Effect Transistors (JFETs) in 1952. Dacey
and Ross improved on it in 1953. In JFETs, Lilienfeld’s
metallic field is replaced by a P-N junction, the metal
contacts are called source and drain, and the field effect
electrode is called a gate. Research in small-signal
MOSFETs continued without any significant improvements
in power MOSFET design, until new products were
introduced in the 1970s.
In March of 1986, Fairchild formed with nine people and
began research on power MOSFETs. 1990’s, Fairchild has
developed a QFET^® devices using planar technology and
low-voltage PowerTrench^® products using trench
technology.
© 2000 Fairchild Semiconductor Corporation
Rev. 1.0.5 • 9/4/13
www.fairchildsemi.com