PROSPECTIVE N-TYPE IMPURITIES AND METHODS OF DIAMOND DOPING

A major goal of diamond thin film technology research has been the rep roducible production of p-n junctions, which are the basic units of ma ny electronic devices. While p-type conductivity is relatively easily attained by boron doping, n-type conductivity has proved much harder t o achieve. The experimental and theoretical results on prospective don or impurities are reviewed. In analogy with classical semiconductors, we will discuss the possibility of obtaining n-type diamond by using s ubstitutional impurity atoms (nitrogen and phosphorus) and interstitia l atoms (Li and Na). New methods of forced diffusion and ion assisted doping during growth are discussed. Methods of forced introduction of impurities into the diamond lattice have an important advantage over t raditional ion implantation methods. Ion implantation introduces struc tural defects (vacancies, vacancy+interstitial, and their combinations ) that are difficult to cure. Both methods, forced diffusion and ion a ssisted doping during growth, introduce no additional structural defec ts, except that inherent to the impurity itself.