EP0143470A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Information recording medium
Assignee: Toshiba Corp
•
Filing: 1984-11-30
•
Granted: —
•
Expires: 2004-11-30
Abstract
Abstract An information recording medium (10) according to the present invention permits recording with high density, reproducing, and erasing using electric charges (18). In particular, a second insulator film (13) thereof is formed as a multi-layer structure with different electric current density and charge trapping density for each layer (13a, 13b). With this recording medium, satisfactory characteristics for recording, reproducing, and erasing can be obtained using films (13) of smaller thickness than for the case of single- layer structure, making it possible to extend the life of the electrode (15) used for recording and erasing through reduction in the voltages required for recording and erasing.
Inventors
- 👤 Toshikazu Matsui
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 20:07
CPC Classifications
G; G11; G11B; G11B9/00; G11B9/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
An information recording medium for recording an information signal by accumulating electric charges in accordance with the information signal, characterised by: a semiconductor base (11); a first insulator film (12) formed on said semiconductor base; and a second insulator film (13) formed on said first insulator film (12) for accumulating electric charges in response to the information signal, said second insulator film comprising a first layer (13a) with large charge trapping density and a second layer (13b) made of the same material as said first layer (13a) so as to have a charge trapping density smaller than that of said first layer (13a), and said second layer (13b) being placed on the opposite side of said first insulator film (12) relative to said first layer (13a).
Claim 2
Dependent Claim
126 words
An information recording medium for recording an information signal by accumulating electric charges in accordance with the information signal, characterised by: a semiconductor base (11); a first insulator film (12) formed on said semiconductor base; and a second insulator film (13) formed on said first insulator film (12) for accumulating electric charges in response to the information signal, said second insulator film comprising a first layer (13a) with large charge trapping density and a second layer (13b) made of the same material as said first layer (13a) so as to have a charge trapping density smaller than that of said first layer (13a), and said second layer (13b) being placed on the opposite side of said first insulator film (12) relative to said first layer (13a).
Claim 3
Dependent Claim
32 words
An information recording medium as claimed in claim 1 characterised in that said second layer (13b) of said second insulator film (13) has smaller electric current density than said first layer (13a).
Claim 4
Dependent Claim
47 words
An information recording medium as claimed in claim 1 or 2 characterised in that said second insulator film (13) further comprises a layer (13c) placed inbetween said first insulator film (12) and said first layer (13a) with similar change trapping density as for said second layer (13b).
Claim 5
Dependent Claim
48 words
An information recording medium as claimed in any one of the preceding claims characterised in that accumulation of electric charges on said second insulator film (13) is accomplished by applying a voltage corresponding to the information signal to an electrode (15) provided on said second insulator film (13).
Claim 6
Dependent Claim
121 words
An information recording medium as claimed in claim 4 characterised in that upon application of a voltage on the electrode (15), there flow electric currents with different magnitudes in each of said first insulator film (12) and the first layer (13a) and the second layers (13b) of said second insulator film (13), and the difference between the electric currents in said first insulator film (12) and the first layer (13a) of said second insulator film (13), as well as the difference between the electric currents in the first layer (13a) and the second layer (13b) of said second insulator film (13), are accumulated in the first layer (13a) of said second insulator film (13) in the form of the electric charges.
Claim 7
Dependent Claim
27 words
An information recording medium as claimed in any one of claims 1 to 5 characterised in that said second insulator film (13) is a silicon nitride film.
Claim 8
Dependent Claim
27 words
An information recording medium as claimed in any one of claims 1 to 6 characterised in that said first insulator film (12) is a silicon oxide film.
Claim 9
Dependent Claim
26 words
An information recording medium as claimed in any one of claims 1 to 7 characterised in that said semiconductor base (11) comprises an N-type silicon crystal.
Claim 10
Dependent Claim
26 words
An information recording medium as claimed in any one of claims 1 to 7 characterised in that said semiconductor base (11) comprises a p-type silicon crystal.
Claim 11
Dependent Claim
36 words
An information recording medium as claimed in claim 6 characterised in that said second insulator film (13) of a silicon nitride has been formed in a high temperature furnace by chemical reaction between ammonia and silane.
Claim 12
Dependent Claim
29 words
ll. An information recording medium as claimed in claim 10 characterised in that said silicon nitride film (13) has been formed with differing mixing ratios of ammonia and silane.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.