Alat semikonduktor: Perbedaan antara revisi

Bila sebuah semikonduktor murni dan tidak ter"eksitasi" oleh sebuah input seperti [[medan listrik]] dia mengijinkanmengizinkan hanya jumlah sangat kecil [[arus (listrik)|arus listrik]] untuk berada dalam dirinya, dan ia merupakan sebuah [[insulator]]. Alasan utama mengapa semikonduktor begitu berguna adalah [[konduktivitas]] semikonduktor yang dapat dimanipulasi dengan menambahkan ketidakmurnian ([[Doping (semikonduktor)|doping]], dengan pemberian sebuah medan listrik, dikenai [[cahaya]], atau dengan cara lain. [[CCD]], sebagai contoh, unit utama dalam [[kamera digital]], bergantung pada kenyataan bahwa konduktivitas semikonduktor meningkat dengan terkenanya sinar. Operasi [[transistor]] tergantung konduktivitas semikonduktor yang dapat ditingkatkan dengan hadirnya sebuah medan listrik.

Mendoping sebuah semikonduktor seperti [[silikon]] dengan atom tidak murni, seperti [[boron]] dan [[phosphorus]], menciptakan jumlah elektron bebas dan lubang yang tidak seimbang. Tingkatan doping yang sangat rendah menyebabkan sebuah semikonduktor berkonduksi, dan karena jumlah pembawa kecil, awan pembawa dapat dengan mudah disapu dari volume semikonduktor dengan medan-e, menciptakan [[zona deplesi]]. Ketika sebuah semikonduktor ter"dop" terdapat lubang yang berlebihan ia disebut sebagai "tipe-p", dan ketika ia terdiri dari elektron bebas yang berlebihan dia disebut "tipe-n". Bahan semikonduktor dalam alat-alat biasanya selalu didop untuk tujuan [[teknik]]. Dan lagi,

Doping a semiconductor such as [[silicon]] with impurity atoms, such as [[boron]] and [[phosphorus]], creates unequal numbers of free electrons and holes. Very low levels of doping cause a semiconductor to conduct, yet because the number of carriers is small, the cloud of carriers can easily be swept from the volume of the semiconductor with e-fields, producing [[depletion zone]]s. When a doped semiconductor contains excess holes it is called "p-type", and when it contains excess free electrons it is known as "n-type". The semiconducting material in devices is almost always carefully doped for [[engineering]] purposes. In fact, junctions between n-type and p-type semiconductors, called [[p-n junction]]s, are the fundamental elements of many semiconductor devices, such as the [[p-n diode]] and the [[bipolar junction transistor]].

The most important semiconductor device in use today is the [[MOSFET]], a type of [[transistor]] whose operation depends on a "gate", from which originates an [[electric field]] that controls the [[conductivity]] of a "channel". MOSFETs, as well as other transistor types, are used as the building blocks of [[logic gate]]s. Their role in a [[microprocessor]] is somewhat analogous to that of [[neuron]]s in the [[brain]]. In [[digital circuit]]s like microprocessors, transistors act as on-off switches; in the MOSFET, for instance, the input gate [[voltage]] determines whether the [[switch]] is on or off.

Transistors also serve very crucial operations in [[analog circuit]]s. Transistors used for analog purposes do not act as on-off switches; rather, they respond to a continuous range of inputs with a continuous range of outputs. For example, transistors are the workhorses of [[amplifier circuit]]s, which produce an amplified, but otherwise identical (ideally), version of the input. For years the [[bipolar junction transistor]], or BJT, was the transistor of choice for analog circuits. However, the [[MOSFET]] has much more desirable properties for digital circuits, and since it is difficult to integrate BJTs and MOSFETs onto a single chip, MOSFETs are now commonly used for both analog and digital purposes.