Fabrication and characterization of silicon P+-N-N+ trapatt diodes

The objectives of the program reported in this thesis were to (a) develop and compare the characteristics of both planar and mesa silicon p+-n-n+ TRAPATT diodes, (b) confirm the validity of Clorfeine's design triangle and (c) examine Chudobiak's technique of pre-selecting diodes capable of stable TRAPATT operation by means of low frequency capacitance measurements. Process development was carried out and both planar and mesa diodes were fabricated. D.C. and low frequency electrical measurements indicated that the fabricated diodes had the characteristics necessary for TRAPATT operation.Initial microwave measurements indicated that both the planar and mesa diodes produced stable TRAPATT oscillations. However, the diodes did not operate at the designed point within Clorfeine's design triangle and the efficiencies were low. Insufficient characterization was carried out to determine the cause of the low efficiencies. The devices were not hermetically sealed and some aging mechanisms appeared to have set in before detailed characterization could be completed, preventing stable oscillations from being achieved. Consequently, detailed comparison of planar and mesa diodes could not be carried out, nor could the design triangle be confirmed.