A study of medium dose Mg implants to achieve shallow p/sup +/ surface layers in Fe doped SI InP is presented. The influence of several parameters, such as the temperature of implants and P co-implant conditions, as well as the post-implant anneals are discussed. It is shown that the out-diffusion of implanted Ma that occurs during rapid thermal annealing (RTA) can be controlled by either InP proximity cap anneals or P co-implants. The undesirable deep in-diffusion can be reduced by performing Mg implants at 200 degrees C or by realizing P co-implants behind the Mg profile. The limitation of Mg solubility in InP is demonstrated to be the principal cause of its low electrical activation. Using the optimized implant and anneal conditions, a maximum of real Mg activation with a high degree of crystal perfection and abrupt shallow p/sup +/ layers in SI InP was achieved.
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