Method of forming a contact-hole of a semiconductor element

• US 5,907,789 A
• Filed: 10/02/1997
• Issued: 05/25/1999
• Est. Priority Date: 01/19/1994
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Komatsu, Hiroshi
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Zarneke, David A
• Application Number:
  US08/943,029
• Time in Patent Office: 600 Days
• Field of Search: 438/592, 438/685, 438/648, 438/649, 438/656, 438/655, 438/683, 438/FOR 360
• US Class Current: 438/649
• CPC Class Codes: H01L 21/28061 the conductor comprising a metal or metal silicide formed by deposition, e.g. sputter deposition, i.e. without a silicidation reaction H01L21/28052 takes precedence
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/28525 the conductive layers comprising semiconducting material H01L21/28518, H01L21/28537 take precedence
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76859 by ion implantation
• CPC Class Codes: H01L 21/76864 Thermal treatment
• CPC Class Codes: H01L 23/485 consisting of layered constructions comprising conductive layers and insulating layers, e.g. planar contacts H01L23/4821, H01L23/4822, H01L23/4824, H01L23/4825 take precedence; materials H01L23/532, bond pads H01L24/02, bump connectors H01L24/10
• CPC Class Codes: H01L 23/53223 Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 29/456 on silicon
• CPC Class Codes: H01L 29/4925 with a multiple layer structure, e.g. several silicon layers with different crystal structure or grain arrangement with only a vertical doping structure or vertical doping variation H01L29/4916
• CPC Class Codes: H01L 29/4933 with a silicide layer contacting the silicon layer, e.g. Polycide gate with a barrier layer between the silicide and silicon layers H01L29/4941
• CPC Class Codes: H01L 29/4975 being a silicide layer, e.g. TiSi2
• CPC Class Codes: H01L 29/4983 with a lateral structure, e.g. a Polysilicon gate with a lateral doping variation or with a lateral composition variation or characterised by the sidewalls being composed of conductive, resistive or dielectric material
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method and an apparatus for making devices with low barrier height. In fabricating an n-channel and p-channel devices, hemisphere grains, silicon crystal grains and metal silicide crystal grains are formed on a contact-hole or a gate electrode on an insulating film in each semiconductor element, so that it becomes possible to control the work function, to reduce the contact resistance, and to control the threshold voltage V_th.

Claims

1. A method of forming a contact-hole of a semiconductor element, comprising the steps of:

forming a source/drain region on a silicon semiconductor substrate having a surface, forming an insulating layer over the whole surface, and forming an opening in the insulating layer over said source/drain region;

forming a metal layer at least in said opening, and implanting ions of an impurity having a same conductivity type as that of said source/drain region in said metal layer, and controlling said impurity so that a desired work function occurs at an interface between a metal suicide layer formed later and the source/drain region;

heating said silicon semiconductor substrate for allowing metal forming said metal layer on a bottom portion of said opening to react with silicon forming said silicon semiconductor substrate thereby forming said metal silicide layer on the bottom portion of said opening, precipitating silicon crystal grains in said metal silicide layer at and near an interface with said source/drain region on the bottom portion of said opening, and activating the impurity implanted and entrapped in said precipitated silicon crystal grains, said desired work function being achieved at said interface by said activated impurity in said metal silicide layer; and

depositing a metallization material at least in said opening.

2. The method of forming a contact-hole of a semiconductor element according to claim 1, wherein said metal layer comprises an element selected from the group consisting of titanium, tungsten, molybdenum and tantalum.

3. The method of forming a contact-hole of a semiconductor element according to claim 1, wherein said metal layer is formed by a physical vapor-phase growth method.

4. The method of forming a contact-hole of a semiconductor element according to claim 1 wherein said metal layer is formed by a chemical vapor-phase growth method.

5. A method of forming a contact-hole of a semiconductor element, comprising the steps of:

forming a source/drain region on a substrate having a surface, forming an insulating layer over the whole surface, and forming an opening in the insulating layer over said source/drain region;

forming a metal silicide layer rich in silicon at least in said opening, and implanting ions of an impurity having a same conductivity type as that of said source/drain region in said metal silicide layer, and controlling said impurity so that a desired work function occurs at an interface between said metal silicide layer and said source/drain region;

heating said substrate for precipitating silicon crystal grains in said metal silicide layer at and near an interface with said source/drain region on a bottom portion of said opening, and activating the impurity implanted and entrapped in said precipitated silicon crystal grains; and

depositing a metallization material at least in said opening.

6. The method of forming a contact-hole of a semiconductor element according to claim 5, wherein said metal silicide layer comprises an element selected from the group consisting of titanium silicide, tungsten silicide, molybdenum silicide and tantalum silicide.

7. The method of forming a contact-hole according to claim 5 wherein said metal silicide layer is formed by a physical vapor-phase growth method.

8. The method of forming a contact-hole according to claim 5 wherein said metal silicide layer is formed by a chemical vapor-phase growth method.