Abstract: Based on Chin's theory,which describes the concentration and compensation ratio dependencies of the low-field mobility in gallium nitride in wide concentration ranges (1e16~1e20cm-3) at room temperature,an analytic model for the compensation ratio of unintentionally doped GaN at room temperature has been obtained.Another model for Si-doped GaN has also been obtained by use of theoretical calculations and computational methods.A comparison of these models with the fitting value from experimental results shows that the new analytic models have a good agreement in the electron concentration range of 3e16～1e18cm-3.

Key words: compensation ratio, gallium nitride, electron drift mobility, Hall mobility, compensating acceptor