A film deposited by electron cyclotron resonance plasma CVD has been successfully applied as a surface passivant for n+p diodes. The ECR‐plasma CVD assures low temperature deposition of film on . The has an excellent interface with with a surface‐state density as low as and a low fixed charge of . Measurement of flatband shifts after exposure to humidity verify that the is more moisture resistant than the conventional passivant. A diode passivated with had a zero bias resistance of at 77 K.