Theoretical and Empirical Studies of Impurity Incorporation into β ‐ SiC Thin Films during Epitaxial Growth

Abstract

The introduction into monocrystalline thin films of the n‐ and p‐type dopants of P and N, and B and Al, respectively, has been studied both theoretically and experimentally via thermodynamic considerations and chemical vapor deposition. The probable gas species which participate in the doping process for these elements has been theoretically investigated by initially determining the stabilities and the gas phase equilibria of the input dopant gases as a function of temperature using free energy minimization calculations. A subsequent experimental study of the amount of incorporation as a function of the partial pressure of the dopant source gas coupled with considerations of dopant incorporation based on a dilute solution model show that Al and P behave ideally while B and N apparently interact with the C or Si in the or fill normally unoccupied interstitial positions. The relationships of atomic concentration or carrier concentration with partial pressure of the dopant gas follow linear and parallel paths. The ratios of ionized dopant concentration to total dopant concentration for N, P, B, and Al are 0.1, 0.2, 0.002, and 0.01, respectively. The solubility limits of N, P, and B in at 1633 K were also determined to be approximately , , and , respectively; that of Al exceeds . The more efficient n‐ and p‐type dopants of N and Al have been used to produce what is believed to be the first p‐n junction diode in a film.