S.V. Bytkin Ukraine, Zaporozhye, bytkin@zp.ukrtel

1. Radiation Hardness Improvement of the SiGe Bipolar Transistors by the Use of the Radiation & Thermal Processing (RTP- technology). S.V. Bytkin Ukraine, Zaporozhye, bytkin@zp.ukrtel.net Bytkin P4 1

2. Abstract Investigated possibility of the Radiation & Thermal Processing (RTP-technology) application for the manufacturing of rad hard SiGe bipolar npn transistors. The effectiveness of the RTP much depends on Ge concentration in the source silicon wafers. Application of the RTP for the transistors made on SiGe allows essentially increase their radiation stability at simplification of the process. Bytkin P4 2

3. RTP-new technology for the radiation hardness improvement. RTP is the process of irradiation of wafers with IC by the flow of -particles with energy 4,5 МeV after creation of the npn transistors by diffusion, but before the deposition of bonding. After irradiation the isothermal annealing of the wafers is carried out for obtaining the relevant h21E values of the output transistors, ensuring reliable operation of the IC. Bytkin P4 3

4. Reasons for the work: in the previous author’s publications was reported, that: • In the most adverse conditions, i.e. at large width of p-base of the bipolar transistor, manufactured on SiGe with germanium concentration 7.5x10^19cm^-3, the increase of its radiation resistance approximately in 4 times can be achieved. • At the certain combination of technical characteristics of the RTP the increase of radiation hardness approximately in 5 times can be achieved. So, there is a question on an opportunity of simultaneous application of RTP and doping of silicon with Ge for increase of radiation stability of bipolar transistors. Bytkin P4 4

5. Ultimate aim of the work: The purpose of the present work is the choice of the combination of the level of the doping of n-Si <Ge> (or SiGe) and level of the preliminary irradiation of bipolar transistors and temperature of their isothermal annealing for the achievement of the maximal radiation hardness Bytkin P4 5

6. Experiment: The full factor experiment of the 22 type was carried outfor the forecastingof the influence of the RTP on the radiation tolerance of bipolar transistors, manufactured on the structures, made on SiGe with 0; 1,3x1019; 2,5x1019; 1,2x1020 cm-3. Matrix of the experiment planning and the chosen intervals of the variation of the RTP factors were identical to the all samples. Bytkin P4 6

7. Radiation hardness (Y) of SiGe bipolar transistors after the different RTP modes. Y= h21E()/h21E(0)) NGe=0 NGe = 1,2x1020cm-3 NGe = 1,2x1019cm-3 Technological annealing temperature, C TID of the technological - irradiation, cm-2 Bytkin P4 7

8. Results of the experiment (I): Obtaining the value Y=1 confirmed, that the application of the preliminary irradiation and annealing of the IC npn of transistors allows essentially increasetheir radiation resistance. Than above used doze of irradiation and the below temperature of an annealing, the less response of a system to irradiation (Y is higher) and, therefore, the radiation stability of the transistor is higher. Bytkin P4 8

9. Results of the experiment (II): The obtained outcomes indicate a capability of the effective application RTP first of all for increase of a radiation stability of SiGebipolar transistors with low Ge content. Achievement of practical independence of the RTP characteristics from the temperature of an isothermal annealing allows considerably simplify realization of a manufacturing process, that allows to speak about its practical usage. Bytkin P4 9