US 4,424,525 AGranted

High electron mobility single heterojunction semiconductor devices

AssigneeFujitsu Limited

InventorTakashi Mimura

Life of this patent

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Abstract

A thin electron accumulation layer is generated along a heterojunction between two kinds of semiconductors each of which has a different electron affinity. This electron accumulation layer suffers less ionized-impurity scattering, because the thickness does not exceed the spread of an electron wave. A channel constituted with this electron accumulation enjoys an excellent electron mobility, particularly at cryogenic temperatures. A layer configuration fabricated with two different semiconductors having different electron mobilities and a similar crystal lattice coefficient, and including a single heterojunction, is effective to improve electron mobility. Such a layer configuration can be employed for production of an active semiconductor device with high electron mobility, resulting in high switching speed. The semiconductor devices including a FET, a CCD, etc., exhibit an excellent transfer conductance Gm.

Claims17

Dependent claims

An active semiconductor device with high electron mobility, comprising

a source layer of a semiconductor doped with donor impurities,
a channel layer of a semiconductor having a larger electron affinity than the semiconductor of the source layer and forming a heterojunction with said source layer, wherein a channel is formed in said channel layer along said heterojunction,
at least one control terminal formed on a selected one of said source and channel layers over said portion of said heterojunction,
a pair of output terminals selectively formed on said source and channel layers, on opposite sides of said at least one control terminal,
said source layer having sufficiently small thickness, at least under said at least one control terminal, so as to be entirely depleted of majority carriers under said at least one control electrode,
wherein said output terminals are electrically connected, at least under said at least one control terminal, only by an accumulation of electrons with high mobility in said channel in said channel layer, depending on a control voltage applied to said control terminal.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/220,968Filed 29 Dec 1980
Priority: JP 54-17102629 Dec 1979
Granted: 3 Jan 1984
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

H10D 30/4755
Having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs: having wide bandgap…
H10D 30/472
High electron mobility transistors [HEMT] or high hole mobility transistors [HHMT]: having lower bandgap active layer formed on top of wider…
H10D 44/40
Charge transfer devices: charge-coupled devices [CCD]
H10D
Inorganic electric semiconductor devices