Hiroshima University

Katsunori Makihara

Seiichiro Higashi

Seiichi Miyazaki

Hideki Murakami

A semiconductor device has a floating gate structure in which charge storage layers are stacked on a SiOlayer formed on a substrate made of n-type Si. The charge storage layer has quantum dots made of undoped Si and an oxide layer that covers the quantum dots. The charge storage layer has quantum dots made of n-Si and an oxide layer that covers the quantum dots. Electrons originally existing in the quantum dots migrate between the quantum dots and the quantum dots via tunnel junction and are distributed in the quantum dots and/or the quantum dots according to the voltage applied to a gate electrode via pads. The distribution is detected in the form of a current (I).

Semiconductor device

A semiconductor memory includes a composite floating structure where an insulation film is formed on a semiconductor substrate, Si-based quantum dots covered with an extremely thin Si oxide film is formed on the insulation film, silicide quantum dots covered with a high dielectric insulation film are formed on the extremely thin Si oxide film, and Si-based quantum dots covered with a high dielectric insulation film are formed on the high dielectric insulation film. Multivalued memory operations can be conducted at a high speed and with stability by applying a certain positive voltage to a gate electrode to accumulate electrons in the silicide quantum dots and by applying a certain negative voltage and weak light to the gate electrode to emit the electrons from the silicide quantum dots.

Semiconductor memory, semiconductor memory system using the same, and method for producing quantum dots applied to semiconductor memory

A semiconductor memory has a composite floating structure in which quantum dots composed of Si and coated with a Si oxide thin film are deposited on an insulating film formed on a semiconductor substrate, quantum dots coated with a high-dielectric insulating film are deposited on the quantum dots, and quantum dots composed of Si and coated with a high-dielectric insulating film are further deposited. Each of the quantum dots includes a core layer and a clad layer which covers the core layer. The electron occupied level in the core layer is lower than that in the clad layer.

Semiconductor memory, semiconductor memory system using the memory, and method for manufacturing quantum dot used in semiconductor memory

A measuring unit applies a dc voltage causing an inversion layer to be formed on an interface between a semiconductor substrate and an insulating film to the semiconductor substrate while changing a change speed of a level of the dc voltage, and measures a current flowing through the insulating film. An arithmetic unit obtains a straight line showing a relationship between the current flowing through the insulating film and the change speed of the dc voltage on the basis of a relationship between the current measured by the measuring unit and the dc voltage, and calculates a slope of the obtained straight line as surface capacitance of the insulating film. The arithmetic unit calculates permittivity of the insulating film on the basis of the calculated surface capacitance, an area of contact between a probe and the insulating film and a thickness of the insulating film.

Measuring apparatus and method for measuring a surface capacitance of an insulating film

A light-emitting device comprises first and second dot members. The first dot member is formed so that it makes contact with the second dot member. The first dot member comprises a plurality of first quantum dot layers. Each of the plurality of first quantum dot layers comprises a plurality of first quantum dots and a silicon dioxide film. The first quantum dot comprises an n-type silicon dot. The second dot member comprises a plurality of second quantum dot layers. Each of the plurality of second quantum dot layers comprises a plurality of second quantum dots and a silicon dioxide film. The second quantum dot comprises a p-type silicon dot.

Growing community of inventors

Higashihiroshima, Japan

Katsunori Makihara