PRODUCTION ENGINEERING MEASURES (PEM) FOR A GERMANIUM MICROWAVE TRANSISTOR.
Quarterly progress rept. no. 7, 31 Dec 65-31 Mar 66.
TEXAS INSTRUMENTS INC DALLAS
Pagination or Media Count:
The emitter window mask and the emitter Top-Hat mask alignment pattern was redesigned in order to aid the operator in accomplishing a faster and more precise alignment of the emitter Top-Hat mask over the KMER emitter window. A precise alignment of the Top-Hat pattern is an essential technique in defining the emitter region of the active device prior to the emitter alloying process. The abnormally low value for the intrinsic f sub T of PEM devices fabricated during the seventh quarter of the contract was corrected by using collector epitaxial material with a lower than normal resistivity value. A study of the problem of abnormally low intrinsic f sub T devices revealed that although the measured resistivity of the epitaxial collector region was as specified, the avalanche breakdown voltage of the fabricated collector-base diode was abnormally high, which in turn indicates an abnormally high value of collector resistivity. Excessive electrical opens were experienced between the emitter and base contacts of the active device during the seventh quarter of this contract. It is believed that the opens problem can be expediently solved by a technique involving the misalignment of the expanded contact Top-Hat pattern during the KMER expanded contact define and etch operation. In addition to the misalignment technique for reducing the number of emitter-base opens, a thinner second silicon dioxide deposition prior to the fabrication of the expanded contact may also aid in reducing open devices. Author
- Electrical and Electronic Equipment
- Fabrication Metallurgy