For

electronic Electronic may refer to: *Electronics, the science of how to control electric energy in semiconductor * ''Electronics'' (magazine), a defunct American trade journal *Electronic storage, the storage of data using an electronic device *Electronic co ...

semiconductor device A semiconductor device is an electronic component that relies on the electronic properties of a semiconductor material (primarily silicon, germanium, and gallium arsenide, as well as organic semiconductors) for its function. Its conductivity li ...

s, a native transistor (or sometimes natural transistor) is a variety of the MOS field-effect transistor that is intermediate between enhancement and depletion modes. Most common is the n-channel native transistor. Historically, native transistors were referred to as

MOSFET The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which d ...

s without specially grown oxide, only natural thin oxide film formed over silicon during processing of other layers. A native

is a transistor with nearly zero

threshold voltage The threshold voltage, commonly abbreviated as Vth or VGS(th), of a field-effect transistor (FET) is the minimum gate-to-source voltage (VGS) that is needed to create a conducting path between the source and drain terminals. It is an important s ...

. Native n-channel transistors have a niche applications in low-voltage

operational amplifier An operational amplifier (often op amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential (relative to c ...

s and in low-voltage digital memory, where it functions as the weak pull-down. It is also used in low-voltage interface circuits. In most

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...

processes, native N-channel

s are fabricated on the "native" slightly p-doped silicon that comprises the bulk region, whereas a non-native N-channel MOSFET is fabricated in a p-well, which has a higher concentration of positive charges due to the increased presence of

holes A hole is an opening in or through a particular medium, usually a solid body. Holes occur through natural and artificial processes, and may be useful for various purposes, or may represent a problem needing to be addressed in many fields of en ...

. The lower concentration of positive charges in the channel of a native device means that less voltage at the gate terminal is required to repel these positive charges and form a

depletion region In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobile ...

under the gate with a conducting channel, which translates to the native device having a smaller

. The main disadvantages of the native transistor are the larger size due to additional doping mask, and sometimes lower

transconductance Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciproca ...

. Native silicon has a lower conductivity than silicon in an n-well or p-well, as most

s are, and therefore must be larger to achieve equivalent conductance. Typical minimal size of the native N-channel

(NMOS) gate is 2-3 times longer and wider than standard

transistor. The cost of chips including native transistors is also increased because of the additional doping operations.

References

External links

Native NMOS circuit example
Transistor types {{Electronics-stub