Thematic Mapper

[1] [2] TM sensors feature seven bands of image data (three in visible wavelengths, four in infrared) most of which have 30 meter spatial resolution.

The upper photo on the right is a 50 times magnification of the combined photomasks used to fabricate the Hughes H4040, the linear silicon photodiode array used in the Thematic Mapper to image the visible bands.

At the time all that was available to manufacture this film was an atmospheric deposition system that basically burned silane (SiH4) in the presence of ammonia in a horizontal tube heated to about 850 °C.

The boron diffused photodiodes had to have very low dark current and high photosensitivity in order to meet the imager specifications.

Also shown on the right is a letter of acknowledgement from Hughes Aircraft Company's Industrial Products Division (IPD) on the invention of the LPCVDs silicon nitride system that made the Thematic Mapper diode arrays possible.

Additionally a photo shows the Hughes (IPD) Newsletter from August 1978 highlighting the second level of aluminium that formed the light shield and set the aperture locations.

J. L. Engle and O. Weinstein, "The Thematic Mapper---An Overview," in IEEE Transactions on Geoscience and Remote Sensing, vol.