This invention describes a field-effect transistor in which the channel is formed in an array of quantum dots. In one embodiment the quantum dots are cladded with a thin layer serving as an energy barrier. The quantum dot channel (QDC) may consist of one or more layers of cladded dots. These dots are realized on a single or polycrystalline substrate. When QDC FETs are realized on polycrystalline or nanocrystalline thin films they may yield higher mobility than in conventional nano- or microcrystalline thin films. These FETs can be used as thin film transistors (TFTs) in a variety of applications. In another embodiment QDC-FETs are combined with: (a) coupled quantum well SWS channels, (b) quantum dot gate 3-state like FETs, and (c) quantum dot gate nonvolatile memories.

Quantum dot circuit and a method of characterizing such a circuit Voltages that enable control of electron occupation in a series of quantum dots are determined by a method of measuring effects of gate electrode voltages on a quantum dot circuit. The quantum dot circuit comprises a channel (10), first gate electrodes (14a-14e) that extend over locations along the edge of the channel to create potentials barriers defining the potentials well therebetween, as well as second gate electrodes (16a-16d) adjacent to potential wells, for controlling depths of the successive electrical potential wells between the potential barriers. First, channel currents are measured in a pre-scan of bias voltages of the first gates for controlling the potential barriers. The result is used to set their bias levels in, a scan over a two-dimensional range of combinations of bias voltages on the second gates for controlling the depths. In this scan an indication of charge carrier occupation of potential wells at consecutive positions along the channel such as electromagnetic wave reflection is measured. Pattern matching with a pattern of crossing occupation edges is applied to the result. This involves a two-dimensional image that has the combinations of the bias voltages as image points and the indication of charge carrier occupation as image values. The pattern matching detects an image point where the image matches a pattern of crossing edges along predetermined directions.

Quantum dot circuit and a method of characterizing such a circuit Voltages that enable control of electron occupation in a series of quantum dots are determined by a method of measuring effects of gate electrode voltages on a quantum dot circuit. The quantum dot circuit comprises a channel (10), first gate electrodes (14a-14e) that extend over locations along the edge of the channel to create potentials barriers defining the potentials well therebetween, as well as second gate electrodes (16a-16d) adjacent to potential wells, for controlling depths of the successive electrical potential wells between the potential barriers. First, channel currents are measured in a pre-scan of bias voltages of the first gates for controlling the potential barriers. The result is used to set their bias levels in, a scan over a two-dimensional range of combinations of bias voltages on the second gates for controlling the depths. In this scan an indication of charge carrier occupation of potential wells at consecutive positions along the channel such as electromagnetic wave reflection is measured. Pattern matching with a pattern of crossing occupation edges is applied to the result. This involves a two-dimensional image that has the combinations of the bias voltages as image points and the indication of charge carrier occupation as image values. The pattern matching detects an image point where the image matches a pattern of crossing edges along predetermined directions.

According to one embodiment, a semiconductor memory includes: a first gate of a first select transistor and a second gate of a second select transistor on a gate insulating film on a semiconductor layer; an oxide semiconductor layer above the semiconductor layer; a first control gate of a first cell and a second control gate of a second cell on an insulating layer on the oxide semiconductor layer; a third gate of a first transistor between the first control gate and the second control gate; a fourth gate of a second transistor between a first end of the oxide semiconductor layer and the second control gate; an interconnect connected to the first end; a source line connected to the first select transistor; and a bit line connected to the second select transistor.