Semiconductor device and method of manufacturing thereof

• US 7,683,455 B2
• Filed: 02/16/2007
• Issued: 03/23/2010
• Est. Priority Date: 07/11/2001
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Inoue, Masao
• Primary Examiner(s): Blum; David S
• Application Number:
  US11/706,956
• Publication Number:
  US 20070138518A1
• Time in Patent Office: 1,131 Days
• Field of Search: 257314-316, 257/499, 257/510, 438/435, 275/10, 27E/290.2, 27E/215.48
• US Class Current: 257/510
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/823481 isolation region manufacturing related aspects, e.g. to avoid interaction of isolation region with adjacent structure
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/7881 Programmable transistors with only two possible levels of programmation H01L29/7888 takes precedence

Abstract

An active region on a semiconductor substrate is electrically isolated by trench isolation. A structure of the trench isolation is constituted of: a trench; a silicon oxide film formed on the inner wall of trench; an oxidation preventive film formed between silicon oxide film and semiconductor substrate; and a filling oxide film filling trench. Gate oxide film is formed by oxidation having a high capability by which radicals of at least one kind of hydrogen radicals and oxygen radicals are generated. Thereby, gate oxide film is formed so as to have a almost uniform thickness such that a thickness of a region directly above oxidation preventive film and a thickness of a region directly below gate electrode are almost the same is each other. According to the above procedure, there are obtained a semiconductor device having good transistor characteristics and a fabrication process therefor.

Claims

1. A semiconductor device comprising:

a semiconductor substrate having a trench at a main surface thereof;

an oxidation preventive film including a nitrogen formed along an inner wall and a bottom surface of said trench;

a filling layer filling said trench with said preventive film located between said filling layer and said semiconductor substrate;

a gate oxide film formed on said main surface of said semiconductor substrate and said oxidation preventive film; and

a gate electrode formed on said gate oxide film,

wherein said gate oxide film has substantially the same thickness in a region directly above said oxidation preventive film and a region directly below said gate electrode and said gate oxide film directly above said oxidation prevention film includes said nitrogen,

wherein said gate oxide film is made according to a method comprising the step of applying a high oxidation capability on said main surface of a semiconductor substrate in an atmosphere in which radicals of at least one kind of hydrogen radicals and at least one kind of oxygen radicals are generated to thereby oxidize an upper surface of the oxidation preventive film and said main surface of said semiconductor substrate.

2. The semiconductor device according to claim 1, wherein said gate electrode has a floating gate electrode and a control gate, insulated from each other.

3. The semiconductor device according to claim 1, wherein said oxidation preventive film is made from at least one of a silicon nitride film and a silicon oxynitride film.