Semiconductor device

Abstract

A semiconductor device such as a DRAM memory device is disclosed. A substrate 12 of semiconductor material is provided with energy band modifying means in the form of a box region 38 and is covered by an insulating layer 14. A semiconductor layer 16 has source 18 and drain 20 regions formed therein to define bodies 22 of respective field effect transistors. The box region 38 is more heavily doped than the adjacent body 22, but less highly doped than the corresponding source 18 and drain 20, and modifies the valence and / or conduction band of the body 22 to increase the amount of electrical charge which can be stored in the body 22.

Description

technical field [0001] The present invention relates to a semiconductor device, in particular but not exclusively to a semiconductor storage device such as a semiconductor memory, and to a substrate for manufacturing such a device. Background technique [0002] The document of International Patent No. PCT / EP02 / 06495 discloses a DRAM device (Dynamic Random Access Memory) comprising a matrix of memory cells, each cell consisting of a field effect transistor. Charge is generated and stored within the bulk of each transistor by applying appropriate voltage pulses between the gate and drain, and between the source and drain of each transistor. The presence or absence of charge represents the "1" and "0" states of a binary data bit, respectively. Memory devices using SOI (Silicon Insulator) type field effect transistors are described in detail in "SOI technology: materials to VLSI", 2nd edition, Kluwer, Boston, 1997. [0003] The transistors used in this type of device are PD-SO...

AI Technical Summary

Problems solved by technology

It is thus impossible to store charge in the body 22, and this type of transistor cannot therefore be used as a storage element.

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