Michael H Kriegel

US Patent:

46024212, Jul 29, 1986

Filed:

Apr 24, 1985

Appl. No.:

6/726558

Inventors:

Joseph Y. Lee - Agoura CA
Michael H. Kriegel - Santa Monica CA
Thomas Y. Chuh - Encinitas CA

Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC

International Classification:

H01L 21477
H01L 2126
H01H 1000

US Classification:

29576C

Abstract:

Low noise polycrystalline silicon resistors are fabricated in the following sequence: (1) deposit an appropriate thickness of polysilicon (e. g. 400 nm) on top of an oxidized wafer (2) resistor doping by ion implantation (e. g. phosphorous) (3) heavy doping of the end-contact regions of the polysilicon resistor by high-dose ion implantation (4) patterning the polysilicon resistor (5) oxidation/annealing the polysilicon resistor (6) open contacts to the polysilicon resistor (7) aluminum metallization to form ohmic contacts (8) a long (e. g. 3 hours) low temperature (e. g. at 375. degree. ) pure hydrogen annealing to passivate the interface states in the polysilicon resistor. Polyresistors processed this way have a noise figure that is about a factor of three lower than samples processed otherwise. The low temperature post metallization annealing in pure hydrogen passivates the interfaces of polyresistors, reducing the l/f noise normally generated therein.