摘要:

Results of InP/GaInAsP interface study using the contact probe profiling method are presented. Results of the interface study are given for λ=1.3 μm laser heterostructures. A correlation is shown between the shape of the interface in the heterostructure and the threshold current of lasers produced from such heterostructures. The correlation of the results with secondary ion mass spectroscopy measurements is also demonstrated. An idea is given of how to detect the very close spaced interfaces with the contact probe method. Its realization with the use of Kr+ion bombardment is shown. In conclusion the ballistic electron emission microscopy is suggested as an attractive new method for characterization of shallow heterostructures.

ISSN:0734-211X    

DOI:10.1116/1.587159

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Silicides are increasingly being used as diffusion sources to form the ultra‐shallow, low resistance source‐drain junctions, which will be needed in the next generation of ultra‐large‐scale integration technology. The silicide thickness and impurity profile in the silicon must be determined accurately as they are critical parameters in determining the performance of the resulting devices. In order to analyze the spreading resistance data measured on silicide structures, the interface between the silicide and silicon must be precisely located. In this article, the use of point‐contact current–voltage (PCI–V) measurements for accurately determining the thickness of ultrathin cobalt silicide–monocrystalline silicon layers is demonstrated. This method is based on the potential barrier, which exists at the probe/silicon interface, but which does not exist at the probe–silicide interface. By monitoring this potential barrier, PCI–Vcan locate the silicide–silicon interface with a resolution of 10 Å.

ISSN:0734-211X    

DOI:10.1116/1.587160

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Advanced spreading resistance measurements and analysis techniques are used to determine the dopant profiles in two ultra‐shallow silicon metal–oxide–semiconductor source/drain structures which were germanium preamorphized prior to implant. Although the two structures differ only slightly in their anneal temperature and time, there is a significant difference in the metallurgical junction depths of the implants. It is proposed that the difference in junction depths is related to defect‐enhanced transient diffusion.

ISSN:0734-211X    

DOI:10.1116/1.587161

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

An accurate doping profile extraction in devices fabricated in semi‐insulating GaAs substrates is difficult. The conventional Schottky barrier diodeC–Vtechnique is prone to large errors caused by bias dependent series resistance, gate current conduction, deep‐level traps, and breakdown of the depletion approximation. It is shown that using both ac admittance (G–VandC–V) and dc (I–V) measurements of Schottky barrier diode the doping profile can be extracted more accurately and the range of accurate measurements can be clearly established. The characterization procedure has been verified experimentally using devices fabricated in a commercial 1 μm GaAs process.

ISSN:0734-211X    

DOI:10.1116/1.587162

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Although theC–Vprofiling technique is usually applied to obtain the doping concentration of lightly doped wells, here we extend it to extract structural information of high‐performance double poly bipolar transistors (BJTs) by comparing profiles taken from two adjacent but distinctC–Vstructures. In particular, the trenching that occurs in unprotected substrate silicon during the gate (base) poly overetch can be measured by the change inp+source/drain implant ton+buried layer depletion width for two such diodes, one with and one without trenching. The diffused extrinsic base junction depth of the double‐poly BJT can be extracted similarly. Both of these physical dimensions must be accurately measured and tracked, to optimize bipolar device performance. Structural measurements by this comparativeC–Vtechnique are nondestructive, simple, and agree with scanning electron microscopy and secondary ion mass spectroscopy within ∼100 Å (5%).  

ISSN:0734-211X    

DOI:10.1116/1.587164

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

The precise control of ion implants for threshold voltage adjustment requires formation of ultra‐shallow electrically active carrier profiles, which begin at the Si–SiO2interface. Obtaining accurate and precise carrier density profiles near the interface with metal–oxide–semiconductor capactiance–voltage (MOSC–V) requires special data acquisition, numerical analysis, and surface corrections. These methods, when applied toC–Vdata collected with a unique, highly repeatable mercury (Hg) probe, provide rapid data acquisition and analysis for threshold adjust implant control in a production environment. Pulsed MOSC–Vmeasurements were used to profile implanted layers with peak carrier densities of ∼1017cm−3, located 15 nm from the Si–SiO2interface.

ISSN:0734-211X    

DOI:10.1116/1.587121

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A numerical method for the determination of ultra‐shallow metal–oxide–semiconductor (MOS) doping profiles and the associated interface trap distribution from measured capacitance–voltage (C–V) characteristics is presented. The method is demonstrated via two cases: (a) theoretical analysis to assess the accuracy of the method; and (b) fabricated MOS test structures, with correlations with spreading resistance profiling (SRP) and secondary ion mass spectroscopy (SIMS). Excellent agreement is seen betweenC–Vand SRP. Our method appears so accurate that it should be considered for routineC–Vanalysis for shallow MOS doping profiles.

ISSN:0734-211X    

DOI:10.1116/1.587122

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Transmission electron microscopy analyses that result in a quantitative characterization of structure/dopant behavior at the nanometer scale are the focus of this research activity. Of particular concern is the quantitative characterization of sequential changes in process‐dependent material features, which impact on structure/dopant behavior for silicon‐based material systems. In order to illustrate the situation, the determination of the vertical and lateral donor distribution is addressed, and the case of diffusion into a 〈100〉 silicon substrate from a patterned structure of arsenic implanted and rapid thermally annealed polysilicon is discussed. The so‐called chemical etching technique is used to delineate arsenic by local variations in the crystal thickness. It is demonstrated that a two‐dimensional isoconcentration contour that maps the arsenic distribution can be quantitatively characterized at the nanometer scale from cross‐sectional transmission electron microscopy data, which are recorded under high‐resolution imaging conditions. The evaluation of microstructural features is briefly considered, and it is concluded that the structure/dopant characterizations that are reviewed in this paper define necessary input parameters for two‐dimensional process and device simulation at 0.25 μm design rules and below.

ISSN:0734-211X    

DOI:10.1116/1.587123

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Quantitative chemical delineation of bothn+andp+junctions in silicon‐based integrated circuits has been achieved and monitored with respect to etching time, temperature, and ultraviolet illumination, using samples prepared by a new planar polishing technique for uniform initial flatness. Junction depths and dopant profiles obtained from cross‐sectional transmission electron microscopy images are compared and cross‐calibrated with both secondary ion mass spectrometry and spreading resistance profiling, confirming that dopant concentrations of 1017cm−3are detected and laterally mapped with 10 nm spatial resolution.  

ISSN:0734-211X    

DOI:10.1116/1.587124

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Electron‐beam induced current (EBIC) was investigated as a possible method of determining shallow junction depth. Molecular‐beam epitaxy Sin+/pjunctions 200–1800 Å deep were explored with both cross‐sectional and plan‐view EBIC geometry. Cross‐sectional EBIC analysis proves to be accurate and reproducible in determining the center of the depletion region for the deep junctions (1800 Å) when using a conventional scanning electron microscopy (SEM) with a LaB6filament. Confidence in the location of shallow junctions decreases due to sample drift and the resolution limits of the SEM and EBIC techniques. In the plan‐view geometry, in which the EBIC current is recorded as a function of electron beam energy, we can distinguish between shallow junctions with greater precision than deeper junctions. Collection efficiency versus electron‐beam energy curves reveal junction depth through shifts in both peak position and height. The collection efficiency versus electron‐beam energy curves were modeled assuming then+layer is equivalent to a Schottky barrier. The model agrees well with peak shifts, but carrier loss due to then+layer must be implemented to sufficiently describe the change in peak height.

ISSN:0734-211X    

DOI:10.1116/1.587125

出版商:American Vacuum Society    

年代:1994

数据来源: AIP