Keithley Instruments has long been an industry leader in both overall parametric test technology and Wafer Level Reliability (WLR) testing. The 4200-SCS software provides a unified measurement interface that guides you through these complex characterization tests so you can understand device behavior quickly. When equipped with the Model 4200-BTI-A Ultra-Fast BTI Package, the Model 4200-SCS parameter analyzer offers the industryâ€™s most advanced NBTI/PBTI test capabilities:
Hot carrier damage occurs in MOS devices when carriers (electrons or holes) are accelerated in the channel. In short channel devices, these electrons/holes attain velocities high enough to cause impact ionization. Impact ionization, in turn, creates extra carriers in the MOS channel. These extra carriers result in significant substrate currents and in some cases attain high enough energy to overcome the semiconductor-oxide barrier and are trapped in the oxide. These trapped channel electrons can cause significant device performance asymmetry and shifts in critical device parameters such as threshold voltage and device drive current. There are a number of Model 4200-SCS project plans for HCI testing: three HCI tests, one electromigration test, and two charge-to-breakdown (Qbd) tests on gate dielectrics using J-ramp and V-ramp methods that follows JEDEC Standard 35-A.
NBTI is a phenomenon where change in the gate-channel interface causes degradation in pMOS device performance. The degradation is typically tracked as the increase of the transistor threshold voltage (VT) and degradation of the drain current (ID). This degradation can reduce yield through failures during burn-in or in the field. The 4200-SCS NBTI test application will monitor and report parameters between two successive stresses including IDoff, IDon, IG, VT, and Gm.
Bias temperature instability is a highly dynamic phenomenon that requires ultra-fast and sensitive measurements for accurate characterization. The Model 4200-BTI-A Ultra-Fast BTI package brings together the measurement capabilities of the Ultra-Fast I-V module and Remote Amplifier/Switch through an intuitive interface that doesnâ€™t compromise test flexibility. The package, which is engineered to provide optimal ultra-fast results without the use of RF structures and interconnects, includes all the hardware and software needed to make the most sophisticated NBTI and PBTI measurements on leading-edge silicon CMOS technology:
The 4200-BTI-A package makes it easy to define stress timing, stress conditions, and a wide range of measurement sequences from spot I, On-The-Fly (OTF), or ID-VG sweeps.
Charge pumping (CP) is a well-known measurement technique for analyzing the semiconductorâ€“dielectric interface of MOS structures. Important information about the quality and degradation of a device can be extracted from charge pumping current (ICP) measurement results, including the interface trap density and the mean capture cross section. Pulsing a gate voltage and measuring a DC substrate current simultaneously is the basis for the various charge pumping methods, so a pulse generator and sensitive DC ammeter are required to make these measurements.
The Model 4200-SCS offers a complete solution for charge pumping measurements. The application test modules use the Model 4200-SMU to measure the charge pumping current (ICP), and the gate is pulsed using the Models 4225-PMU.
4200-SCS Parameter Analyzer Mainframe
The 4200-SCS is a modular, fully integrated parameter analyzer that performs electrical characterization of devices, materials or processes. With nine measurement slots and a built-in low noise ground unit, you can configure it to precisely meet your test requirements or budget constraint.
Ultra-Fast I-V Modules
Each Model 4225-PMU module provides two channels of integrated sourcing and measurement but occupies only a single slot in the Model 4200-SCS's nine-slot chassis. Unlike competitive solutions, each channel of the Model 4225-PMU combines high speed voltage outputs (with pulse widths ranging from 60 nanoseconds to DC) with simultaneous current and voltage measurements. Each 4200-SCS chassis can accommodate up to six Model 4225-PMU modules, for a maximum of twelve ultra-fast source and measure channels.
The Model 4225-PMU can be used to perform three types of ultra-fast I-V tests: Pulsed I-V, Transient I-V, and Pulsed Sourcing. Pulse and transient measurements add a time domain dimension to your analysis and allows for dynamic characteristics to be explored. Using pulsed I-V signals to characterize devices rather than DC signals makes it possible to study or reduce the effects of self-heating or minimize current drift due to trapped charge. Pulsed sourcing can also be used to stress test a device during reliability cycling or program & erase memory devices.
SMUs are precision instruments which are used for sourcing current or voltage and simultaneously measuring current and voltage with high accuracy and speed.
Two SMU models are available for use with the 4200-SCS, the 4200-SMU medium power SMU or 4210-SMU high power SMU. Both models occupy only one instrument slot and up to a total of nine can be installed in the 4200-SCS.
Offering the industryâ€™s widest dynamic range, the medium power 4200-SMU operates from 100 nA to 100 mA and 1 uV to 210 V and the high power 4210-SMU operates up to 1 A. The low current measurement capabilities of either SMU can be extended to 0.1 fA resolution by adding an optional preamplifier.
Remote Amplifier/Switch Units
The low current measurement capabilities of the Ultra-fast I-V module can be extended by adding the 4225-RPM. Additionally, the RPM acts as a multiplex switch, allowing you to automatically switch between SMUs, C-V or Ultra-fast I-V modules.
The six slot Model 707B and the single slot 708B semiconductor switch matrix mainframes gives you the ability to control up to 2,880 channels or matrix crosspoints in real time, making these systems ideal for applications like semiconductor device characterization, wafer level reliability, parallel testing, and modeling. The large matrix capacity (576 and 96 channels) of the mainframes can be increased by connecting up to five mainframes in a master/slave configuration that can be controlled from a single GPIB address.
One of the most difficult problems when making I-V, C-V and Pulsed I-V measurements is that the cables required for each measurement type are fundamentally different. Guarding is necessary to achieve low current I-V measurements, which makes triaxial cables necessary. C-V measurements use four coaxial cables with the outer shells connected together. Pulsed measurements require the highest bandwidth of the three measurement types, so the cable must have a characteristic impedance that matches the source impedance to prevent reflections. Multi-Measurement Performance Cables (MMPC) simplifies switching between DC I-V, C-V, and pulsed I-V testing configurations. No matter what type of measurement is being made, you won’t have to change the probe manipulator cabling just move the cables from one instrument module to another. In addition, you can change the setup while the probe needles stay in contact with a wafer, reducing pad damage and maintaining the same contact impedance for all three types of measurements. MMPC Cables are available for select Cascade Microtech, Suss, Lucas Signatone and Wentworth probe stations.
The 4200-SCS can control external equipment such as an automated or semi-automated probe stations, temperature controllers etc. Probe drivers are supplied with the 4200-SCS for select Cascade Microtech, Suss, MicroManipulator and Signatone probe stations.
Device Under Test (DUT)
The 4200-SCS is capable of testing many cutting-edge devices or materials such as: