Keithley 2535 Hot Carrier AN free download

File name 2535_Hot_Carrier_AN.pdf

Number 2535 Application Note Monitoring Channel Hot Carrier (CHC) Series Degradation of MOSFET Devices using Keithley Model 4200-SCS Introduction Pre-Stress characterization Channel Hot Carrier (CHC) induced degradation is an important reliability concern in modern ULSI circuits. Charge carriers gain Fail? Yes Stop kinetic energy as they are accelerated by the large electric field No across the channel of a MOSFET. While most carriers reach the Record data drain, hot carriers (those with very high kinetic energy) can gen- erate electron-hole pairs near the drain due to impact ionization Stress Yes from atomic-level collisions. Others can be injected into the gate Fail? channel interface, breaking Si-H bonds and increasing interface Increase stress time No trap density. The effect of CHC is time dependant degradation of Interim test device parameters, such as V T, IDLIN, and IDSAT. This channel hot carrier induced degradation (also called Record data HCI or hot carrier injection) can be seen on both NMOS and No Yes Fail/Exit PMOS devices and will affect device parameters in all regions, such as V T, sub-threshold slope, Id-on, Id-off, Ig, etc. The rate of degradation of each parameter over stress time depends on the Figure 2. Typical CHC test procedure device layout and process used. Stress bias conditions are based on worst-case degradation Vg bias conditions, which are different for