Browse Prior Art Database

DC Sputtering Amorphous Semiconductors

IP.com Disclosure Number: IPCOM000078910D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR [+2]

Abstract

A method of DC sputtering of amorphous semiconductors is suggested, which utilizes crystalline form of the semiconductor to obtain conductivity of the target. Normally, a RF field in the megahertz range is generally used to sputter amorphous semiconductors and insulators. A DC field passivates the surface of the source with a positive charge that prevents sputtering. However, RF sputtering has two disadvantages in comparison to DC. These are: (1) it causes dielectric heating of the substrate, therefore heat sinking is critical; (2) stoichiometry is difficult to control. Substrate film resputtering rates are significant.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 97% of the total text.

Page 1 of 1

DC Sputtering Amorphous Semiconductors

A method of DC sputtering of amorphous semiconductors is suggested, which utilizes crystalline form of the semiconductor to obtain conductivity of the target. Normally, a RF field in the megahertz range is generally used to sputter amorphous semiconductors and insulators. A DC field passivates the surface of the source with a positive charge that prevents sputtering. However, RF sputtering has two disadvantages in comparison to DC. These are: (1) it causes dielectric heating of the substrate, therefore heat sinking is critical; (2) stoichiometry is difficult to control. Substrate film resputtering rates are significant.

It has been determined that amorphous semiconductors of the As-Se-Te type can be sputtered from a target of the same composition in its crystalline state. The resulting films are amorphous with high resistivities. It is not necessary to thermally contact the substrates to the cooling block.

Sources of three different compositions are: (1) As(2)Te(3), 1(As(2)Se(3)) + 2(As(2)Te(3)), and (3) As(5)Te(20)Se(75).

The first two compositions are crystallized by slowly cooling from the melt at 300 degrees C/hr. The third which is highest in selenium, is annealed 48 hours at 100 degrees C to crystallize.

All three sources are sputtered in argon between one and two kilovolts. Rates vary from 19 to 65 angstroms/min. The As(5)Se(75)Te(20) source is not capable of being sputtered in its amorphous state. However, yields of...