Effect of Transistor Design Parameters on Radiation Response (Surface Effects)

摘要

During this program, the relationship between various transistor surface conditions and transient device leakage currents (delta I sub CBO) due to radiation exposure were studied. These studies were made by utilizing both 2N708 type transistors with various surface treatments, and similarly treated groups of n type silicon bars. The primary surfaces studied were (1) oxidized, (2) sandblasted, etched, and mechanically polished. Additionally, an analytical model describing the predominate mechanism of surface radiation effects was developed. This relationship was tested against the experimental data and order of magnitude agreement was found. The program has led to the following conclusions: (1) At a given value of surface recombination velocity, the radiation induced response, delta I sub CBO, in a device is less for smaller values of minority carrier lifetime. Thus, no device characteristic compromise is necessary to achieve maximum device radiation resistance. (2) A small increase in radiation resistance can be achieved in a device by increasing surface recombination velocity. However, the improvement in radiation resistance is obtained at the cost of decreased transistor gain and increased leakage currents. (Author)