高能分辨率深能級瞬態(tài)譜儀器(DLTS)

1、DLTS Presentation Deep Level transient SpectroscopyPioneers in Measurements of Depth*picture taken from Serway, Raymond A., Beichner, Robert J. and Jewett, John W. Physics for Scientists and Engineers 5th Edition, Saunders College Publishing: Orlandon, FL, 2000Motivation: Measuring the Depth of Defe

2、ct Related Traps in SemiconductorsCarrier TrappingConductance BandValence BandDefect LevelTrap depthEnergy-Carrier EscapekTLow TemperaturekTslowfastHigh Temperature-History of DLTS The DLTS Technique was developed in 1974 by D V Lang as an extension to traditional Thermally Stimulated Transient Capa

3、citance (TSCAP). It is now well established as a method to quantify electrically active deep levels. It is complementary to other analytical techniques such as SIMSHow are these levels characterized? The levels are characterized by a “Fingerprint” which includes: Energy Concentration (amount of defe

4、cts present) Capture Cross Section (effectiveness of the level)a) Schottky barrier under reverse bias VRb) Schottky barrier with fill pulse applied. Deep levels forced under the Fermi level fill with carriersc) Thermal emission of carriers from filled deep levels now above the Fermi level as the ful

5、l pulse endsd) Capacitance changes observed as the bias on the test sample is changed = full deep level = empty deep level(a)(b)(c)VpVRAutomatic Arrhenius PlotDigital DLTSIsothermal Applications Fully automated and VERY FAST trap profiling with depth:varying pulse bias, reverse bias or both capture

6、cross section with pulse widths to 8ns possible ICTS - like analysis (variation of Tw and temperature) for a thorough and accurate investigation of a single isolated DLTS peak for extending cryostat range for measuring temperature sensitive devicesDigital DLTSMOS/MIS Application MOS/MIS measurement

7、and evaluation using by pulsed C-V and DLTS in addition to Zerbst Analysis (C-t characterisation) evaluation of generation processes measurement of interface state density oxide qualityBasic Hardware Options Nitrogen Cryostat Micromanipulator probes Helium Cryostat Small lightweight probes Capacitan

8、ce bridge 15mV or 100mV 100V power supply option ( 20V is standard)Variable Transient Period Width MeasurementBibliography for DLTSsome examples of DLTS on a wide variety of materialsCdTeLeigh, W.B. and Kremer R.B. Deep Level Defects in CdTeMat. Res. Symp. Proc. Vol 10 241 1987 MRS.CdTeCollins, R.T.

9、, Kuech, T.F. and Mcgill, T.C. DLTS Study of deep levels in n-type CdTeJ. Vac. Sci. Technol. 21 (1) 191 1982ExtendedPeaker, A.R., Kaniewsak, M Kaniewsak J., Evans, J.H., Hamilton, B. and Lorimer GDefects Characterization of the Electronic Properties of Extended Defects in Silicon Electrochem. Soc. P

10、roc. Vol 91-99 125 1991Cr and VSadoh, T., Watanabe M., Nakashima, H. and Tsurushima, T.,(Si)Deep Levels of Vanadium and Chromium-Hydrogen complexes in Silicon17th International Conference on Defects in Semiconductors, Gmunden July 18-23 1993DX CentresDobaczewski L, Kaczor P., and Peaker, A.R. Fine s

11、tructure observed in thermal emission process for the EL2 Defect in GaAs 17th International Conference on Defects in Semiconductors,Gmunden July 18-23 1993SiGeErzgrber, H.B., Kissinger, G., Krger, D., Morgenstern, T., Schmalz, K., Shilz, J., Kurten, K. and Osinsky, A. Point defects in SiGe expitaxia

12、l layers and Bulk Crystals 17th International Conference on Defects in Semiconductors, Gmunden July 18-23 1993InPWalters, R. J. and Summers, G.P. Deep Level Transient Spectroscopy Studies of Proton inrradiatedp-type InP J. Appl. Phy. 69 (9), 6488, 1991Zn in SiWeiss, S., Beckmann, R. and Kassing, R.

13、The Electrical Properties of Zinc in Silicon Appl. Phys. A 50 151-156 1990FT-DLTSWeiss, S., and Kassing R. Deep Level Transient Fourier Spectroscopy (DLTFS)- A technique for the Analysis of Deep Level Properties Solid St. Electronics 31 (12), 1733-1742 1998ZnSe (Au)Besomi, P., and Wessels, B. W. Dee

14、p Level Defects in Au/ZnSe Schottky diodesElectronics Letters 16 (21), 794 1980CdSBesomi, P., and Wessels, B. W. Deep Level Defects in Polycrystalline cadmium sulfideJ. Appl. Phys. 51 (8) 4305 1980Bibliography for DLTSsome examples of DLTS on a wide variety of materialsPhystech FT1030Pos.1: HERA-DLTS Electronic including Boonton 7200 capacitance meter Pos.2: HE-1020 Complete Software Soft ware package Pos.3: Constant Capacitance option Pos.4: 100