Patent ID: 6603679
Filing Date: 2003-08-05
Classification: G11C

Abstract:
A coupling coefficient measuring method for a semiconductor memory having a first gate electrode and a source region coupled at a prescribed electrostatic coupling ratio, comprising steps of:increasing a source; voltage while setting a drain voltage to a first drain, voltage defining a reference value for measuring a first subthreshold current flowing through a first transistor having said first gate electrode as a gate; increasing said source voltage while setting said drain voltage to a second drain voltage higher by a prescribed value than said first drain voltage for measuring a second subthreshold current flowing through said first transistor; reading a first source voltage corresponding to a first value of said first subthreshold current and a second source voltage corresponding to a second value of said second subthreshold current equal to said first value; and calculating the ratio of the difference between said first drain voltage and said second drain voltage to the difference between said first source voltage and said second source voltage thereby obtaining the coupling coefficient between said first gate electrode and said source region.