Protection element and method of manufacturing same

• US 5,225,896 A
• Filed: 08/06/1991
• Issued: 07/06/1993
• Est. Priority Date: 02/01/1989
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Nagalingam, Samuel J. S., Van Roozendaal, Leonardus J.
• Primary Examiner(s): Jackson, Jr., Jerome
• Assistant Examiner(s): Monin, D.
• Application Number:
  US07/741,983
• Time in Patent Office: 700 Days
• Field of Search: 357/71, 357/7.15, 357/51, 357/23.13, 357/35, 357/67
• US Class Current: 257/356
• CPC Class Codes: H01L 27/0259 using bipolar transistors as protective elements

Abstract

A semiconductor device comprises a semiconductor body (1) of silicon having a monolithic integrated circuit with a field oxide pattern (2) having at least one protection element (T2) having at least one active zone (4) of a first conductivity type, which adjoins at least in part the field oxide (2) and forms with the adjoining silicon region (5) of the second opposite conductivity type a pn junction (6). The active zone (4) is contacted with an electrode layer (7), which is connected to a point (G) of the semiconductor device to be protected against static discharge. The electrode layer (7) consists of a metal silicide. According to the invention, the metal silicide (7) also extends onto the field oxide (2) adjoining the active zone (4) over a certain distance, which is preferably at least 0.5 μm.

Claims

1. A semiconductor device having an electrostatic charge protector comprising:

(a) a semiconductor body of silicon of a first conductivity type,

(b) at least one monolithic integrated circuit disposed in said semiconductor body,

(c) a field oxide pattern disposed to separate at least portions of said integrated circuit,

(d) at least one protection element having at least one active zone of a second conductivity type, said at least one protection element being disposed to adjoin said field oxide pattern at least in part opposite to said integrated circuit, and said at least one protection element having a pn junction with said semiconductor body, and

(e) a metal silicide electrode layer disposed in contact both with said at least one active zone and with said field oxide pattern to protect against electrostatic discharge, said metal silicide electrode layer being disposed on said field oxide pattern for a given distance of at least 0.5 μ

m from an edge with said at least one active zone and being disposed on said at least one active zone for a second given distance of about 1.0 μ

m from said edge,

wherein electrostatic discharge is prevented by said metal silicide electrode layer and said at least one protection element, and

wherein said protection element includes two active zones separated by said field oxide pattern, and wherein said metal silicide electrode layer is disposed onto said field oxide pattern from opposite sides with a separation of about 0.9 μ

m.

2. A semiconductor device according to claim 1, wherein said metal electrode layer is titanium silicide.

3. A semiconductor device according to claim 1, wherein said metal silicide electrode layer is disposed to maintain an increased distance from said pn junction.

4. A semiconductor device according to claim 1, wherein said at least one protection element is a bipolar transistor.

5. A semiconductor device according to claim 4, wherein at least two of said active zones are disposed with respect to said bipolar transistor, said two active zones respectively constituting a collector zone and an emitter zone of a lateral bipolar transistor.

6. A semiconductor device according to claim 1, wherein the active zone of said at least one protection element is part of a diode, said diode providing electrostatic protection upon temporary connection in a reverse direction during operation.

7. A semiconductor device according to claim 1, wherein each of said at least one active zones includes a first weakly doped region in contact with said pn junction and a second highly doped region in contact with said metal silicide electrode layer, said first and second regions being disposed together.