Oxygen control in Al-based III-V epiwafers by SIMS for yield improvement

Summary form only given. We show a very successful example of SIMS control to qualify epiwafers for the control of oxygen contamination. It is known that oxygen in III-V compounds can compensate dopants and reduce the luminescence efficiency and that the oxygen contamination is a common problem in MOCVD growth of Al-based III-V compounds. Since Al is highly reactive with oxygen, even a very small amount of oxygen in the growth system can produce a high oxygen contamination. The cause of the oxygen presence is a complex problem and it can come from different sources such as system leakage, memory effects and a contaminated source. The tolerance of oxygen contamination can be from low 1E16 to high 1E18 atoms/cm/sup 3/ depending upon the device type. The challenge for SIMS analysis is to routinely keep such low detection for oxygen and to provide consistent measurements. A protocol for this purpose has been developed. Oxygen detection limits in AlGaAs over 40 weeks, obtained with a Cameca instrument, are shown. The implications of such control for LED, laser and HEMT production yield are presented. The possibility of analyzing up to 4" wafers by SIMS is discussed.