Experiment Name : MOS Capacitor
About the Experiment:
Maintaining the quality and reliability of gate oxides is one of the most critical and challenging tasks in any semiconductor fabrication. Electrical characterization and monitoring is critical for maintaining gate oxide uniformity. Many electrical characterization techniques have been developed over the years to characterize gate dielectric quality. However, the most commonly used tool for studying gate oxide quality in detail is the Capacitance-Voltage (C-V) technique. C-V test results offer a wealth of device and process information, including bulk and interface charges and many MOS-device parameters.
The importance of C-V measurement techniques is that alarge number of device parameters can be extracted from the high frequency C-V curve that is described here and the quasistatic C-V curve. These parameters can provide critical device and process information. We can divide the parameters roughly into three groups. The first group includes typical MOS device parameters such as flatband voltage, threshold voltage, etc. The next group, oxide charge parameters, includes interface trap charge density, mobile ion charge density, etc. The third group consists of doping-related parameters. Also, using C-t data, carrier generation lifetime and recombination lifetime can be extracted. In particular, various current-voltage (I-V) characterization methods have been developed, including the following:
Time-Dependent Dielectric Breakdown (TDDB), Charge to Breakdown (QBD)
Tunneling Current (Fowler-Nordheim or Direct Tunneling)
Stress-Induced Leakage Current (SILC)