抄録
Spin-lattice relaxation rate, 1⁄Ts, of donor electrons in phosphorus and boron doped silicon was studied at liquid helium temperature as a function of the degree of compensation K=NA⁄ND (NA, ND: acceptor and donor concentrations). Donor concentrations ranged from approximately 5×1015/cc to 3×1016/cc and the degree of compensation was varied up to 0.8. It was found that 1⁄Ts increased first with increasing K, reached a maximum at around K=0.5∼0.6 depending on ND, and then decreased with a further increase in K. If a power law is assumed for the dependence on temperature T, the relaxation rate goes as Tn, n increasing with K but being independent of ND.
The above experimental results are discussed assuming the hopping of donor electrons. A comparison is made with Sugihara’s theory, which gave a rather satisfactory explanation of the experimental results.
