For electronic

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 conductivit ...

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 upright=1.3, Two power MOSFETs in amperes">A in the ''on'' state, dissipating up to about 100 watt">W and controlling a load of over 2000 W. A matchstick is pictured for scale. In electronics, the metal–oxide–semiconductor field- ...

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 direct coupling, DC-coupled Electronic component, electronic voltage amplifier with a differential input, a (usually) Single-ended signaling, single-ended output, and an extremely high gain ( ...

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 MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

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. 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 mobil ...

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 recipro ...

. 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