Planar process and structure for spectral filters in an optoelectronic device

Claim 2

A bandpass spectral filter comprised of: a substrate (12); a first oxide layer (14) of a predetermined thickness formed on said substrate; a polysilicon layer (16) of a predetermined thickness formed on said first oxide layer; a second oxide layer (18) of a predetermined thickness formed on said polysilicon layer; and a nitride layer (20) of a predetermined thickness formed on said second oxide layer (FIG. 2).

Claim 3

A band reject spectral filter comprised of: a substrate (30); alternating layers (32-40) of a predetermined thicknesses of nitride and oxide formed on said substrate, with the top and bottom layers each being formed of nitride (FIG. 6).

Claim 4

A band reject spectral filter comprised of: a substrate (30); alternating layers (32-40) of a predetermined thicknesses of nitride and oxide formed on said substrate, with the top and bottom layers each being formed of nitride (FIG. 6).

Claim 5

The combination as recited in claims 1 or 2, wherein said substrate (12, 30) is formed of silicon or glass.

Claim 6

The combination as recited in one of the preceding claims, wherein said nitride layers are silicon nitride and said oxide layers are silicon oxide.

Claim 7

The combination as recited in one of the preceding claims, adapted for a monolithic optoelectronic device wherein the substrate (12, 30) includes a photocollec­tion area.

Claim 8

The combination as recited in one of claims 1 or 2 to 5, wherein said filter is comprised of red, green and blue sections (6, 8, 10).

Claim 9

The combination as recited in claim 6, wherein: said red section (6) has a first silicon oxide layer thickness on the order of 0.085 microns, a polysilicon layer thickness on the order of 0.0975 microns, a second silicon oxide layer thickness on the order of 0.118 microns and a silicon nitride thickness on the order of 0.095 microns; said green section (8) has a first silicon oxide layer thickness on the order of 0.070 microns, a polysilicon layer thickness on the order of 0.0683 microns, a second silicon oxide layer thickness on the order of 0.044 microns and a silicon nitride layer thickness on the order of 0.120 microns; and said blue section (10) has a first silicon oxide layer thickness on the order of 0.125 microns, a polysilicon layer thickness on the order of 0.0370 microns, a se­cond silicon oxide layer thickness on the order of 0.014 microns, and a silicon nitride layer thickness on the order of 0.100 microns (FIG. 2).

Claim 10

The combination as recited in one of the claims 2 to 5, wherein each silicon nitride layer (32, 34, ...) has a layer thickness on the order of 200 microns and each silicon oxide layer (42, 44, ...) has a layer thickness on the order of 125 microns (FIG. 6)

Claim 11

The combination as recited in claim 8, wherein there are five silicon nitride layers and four silicon oxide layers.

Claim 14

The method as recited in claim 10 for forming a multi­layer bandpass spectral filter, comprised of a plurality of red, green and blue sections (6, 8, 10), and includ­ing the steps of: overlaying said substrate (12) with a first layer (14) of silicon oxide having in each red section (6) a layer thickness on the order of 0.070 microns and having in each blue section (10) a layer thickness on the order of 0.125 microns; overlaying said first layer (14) of silicon oxide with a layer (16) of polysilicon having in each red section a layer thickness on the order of 0.975 microns, having in each green section a layer thickness on the order of 0.683 microns ad having in each blue section a layer thickness on the order of 0.037 microns; overlaying said layer (16) of polysilicon with a second layer (18) of silicon oxide having in each red section a layer thickness on the order of 0.118 microns, having in each green section a layer thickness on the order of 0.044 microns and having in each blue section a layer thickness on the order of 0.014 microns; and overlaying said second layer (18) of silicon oxide with a layer (20) of silicon nitride having in each red section a layer thickness on the order of 0.095 microns, having in each green section a layer thickness on the order of 0.120 microns and having in each blue section a layer thickness on the order of 0.100 microns.