Semiconductor die attachment for high vacuum tubes

The method of manufacturing a high vacuum tube in which a semiconductor die is bonded onto an inner surface of a package comprising:

• creating multiple bonding pads at a first surface of a die,
• creating multiple matching bonding pads at the inner surface of the package, said package comprising a different material from said first surface of said die,
• placing between said sets of bonding pads a die bond material with a melting point of less than about 150° C.,
• aligning the surfaces with said bonding pads together,
• placing a photocathode into a facing relationship with a second surface of said die,
• placing a spacer between said photocathode and said second surface of said die, and
• carrying said photocathode, said spacer, and said die while in a contacting relationship and aligned together through a brazing cycle and then through an ultra high vacuum processing cycle resulting in a sealed vacuum tube.