High-temperature stability of Au Pt/ n-GaAs Schottky barrier diodes
Abstract
The operating surface temperature for the Au/Pt/ n-GaAs Schottky barrier microwave devices is in the temperature range of 200-250°C. In order to determine operating lifetimes for these devices accelerated aging studies were performed. In this study the reverse bias voltage at currents of 10 μA, 100 μA and 1 mA were determined as a function of annealing time at 350°C for diodes metallized with AuPt and with Pt alone. Two distinct degradation mechanisms were observed. (a) Penetration of Au by diffusion through thin Pt films or by surface migration along edges or cracks in the Pt films resulted in rapid degradation of the devices. (b) The second degradation mechanism was observed in absence of Au and was found to be related to annealing ambient and the metallurgical interaction between Pt and GaAs. A decrease in the reverse bias voltage was observed due to the diffusion of oxygen from the interfacial oxide and from the ambient. Oxygen from the ambient diffused throug platinum into GaAs and was the cause of the final degradation of devices annealed in air. An increase in the reverse bias voltage occurred immediately after the initial decrease due to the interfacial oxide. This recovery has been attributed to the metallurgical interaction between Pt and GaAs which led to the formation of PtAs 2 at the interface and GaPt phases away from the interface.
- Publication:
-
Solid State Electronics
- Pub Date:
- August 1974
- DOI:
- 10.1016/0038-1101(74)90037-9
- Bibcode:
- 1974SSEle..17..869M
- Keywords:
-
- Gallium Arsenides;
- High Temperature Tests;
- Metal Films;
- Microwave Equipment;
- Schottky Diodes;
- Thermal Stability;
- Barrier Layers;
- Electrical Faults;
- Electronic Equipment Tests;
- Gold Coatings;
- Junction Diodes;
- Operating Temperature;
- Platinum;
- Surface Temperature;
- Volt-Ampere Characteristics;
- Electronics and Electrical Engineering