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The results of a theoretical study of the effects of the strain on the cutoff frequencies of SiGe HBTs are presented. The influence of the strain on the base resistance and transit time, and through them on high-frequency performance, was taken into account. The positive role played by the strain is demonstrated.
This paper presents a physics-based model describing the current-induced formation of a parasitic barrier in the conduction band at the base collector heterojunction in npn SiGe heterojunction bipolar transistors (HBTs). Due to the valence band discontinuity DELTA E(sub v), hole injection into the collector at the onset of base pushout is impeded, which gives rise to formation of a barrier to electron transport which degrades the device's high frequency performance. In this paper, we present results from an analytical model for the height of the barrier calculated from the device's structure as a function of the collector junction bias and collector current density.
Multifinger SiGe HBTs have been fabricated using a novel fully self-aligned double-mesa technology. With the novel process technology, a common-emitter 2x2x30 sq micrometer device exhibits high maximum oscillating frequency (f(sub max)) and cut-off frequency (f(sub T)) of 78 and 37 GHz, respectively. In class-A operation, a multifinger device with l0x2x30 sq micrometer emitter is expected to provide an output power of 25.6 dBm with a gain of 10 dB and a maximum power added efficiency (PAE) of 30.33% at 8 GHz.
The electronic Structure and Properties of SiGe are important in determining the characteristics of many new hot-carrier devices, including the heterostructure bipolar transistor.
SiGe HBT heavy ion current transients are measured using microbeam and both high- and low-energy broadbeam sources. These new data provide detailed insight into the effects of ion range, LET, and strike location.
SiGe HBT heavy ion-induced current transients are measured using Sandia National Laboratories microbeam and high- and low-energy broadbeam sources at the Grand Accelerateur National d'Ions Lourds and the University of Jyvaskyla. The data were captured using a custom broadband IC package and real-time digital phosphor oscilloscopes with at least 16 GHz of analog bandwidth. These data provide detailed insight into the effects of ion strike location, range, and LET.
IBM 5AM SiGe HBT is device-under-test. High-speed measurement setup. Low-impedance current transient measurements. SNL, JYFL, GANIL. Microbeam to broadbeam position inference. Improvement to state-of-the-art. Microbeam (SNL) transients reveal position dependent heavy ion response, Unique response for different device regions Unique response for different bias schemes. Similarities to TPA pulsed-laser data. Broadbeam transients (JYFL and GANIL) provide realistic heavy ion response. Feedback using microbeam data. Overcome issues of LET and ion range with microbeam. **Angled Ar-40 data in full paper. Data sets yield first-order results, suitable for TCAD calibration feedback.
A fully integrated, front-end Ka-band monolithic microwave integrated circuit (MMIC) was developed that houses an LNA (low noise amplifier) stage, a down-conversion stage, and output buffer amplifiers. The MMIC design employs a two-step quadrature down-conversion architecture, illustrated in the figure, which results in improved quality of the down-converted IF quadrature signals. This is due to the improved sensitivity of this architecture to amplitude and phase mismatches in the quadrature down-conversion process. Current sharing results in reduced power consumption, while 3D-coupled inductors reduce the chip area. Improved noise figure is expected over previous SiGe-based, frontend designs
A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder.
We present results on heavy-ion and proton irradiations for commercial SiGe BiCMOS operational amplifiers: LTC6400-20 from Linear Technology and THS4304 from Texas Instruments. We found that the devices are susceptible to heavy-ion-induced SETs. The SET cross-sections increase with increasing operating frequency. The LTC6400 exhibits a LET(sub th) < 7.4 MeV·sq cm/mg for frequencies ranging from 10 to 1000 MHz. The THS4304 exhibits a LET(sub th) < 4.4 MeV·sq cm/mg at 200 MHz; the LET(sub th) decreases with increasing frequency. The significance of the SETs also increases with frequency. The SETs at 1000 MHz can erase several signal cycles. We al.so found that the LTC6400 is relatively robust against 198 and 54 MeV protons. We did not observe angular sensitivity from the proton irradiations.
Here, we investigate carrier transport in silicon–germanium nanowires with an axial p–n junction doping profile by fabricating these wires into transistors that feature separate top gates over each doping segment. By independently biasing each gate, carrier concentrations in the n- and p-side of the wire can be modulated. For these devices, which were fabricated with nickel source–drain electrical contacts, holes are the dominant charge carrier, with more favorable hole injection occurring on the p-side contact. Channel current exhibits greater sensitivity to the n-side gate, and in the reverse biased source–drain configuration, current is limited by the nickel/n-side Schottky contact.
V10(GeSi)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent V sites. In the first V site, V is bonded in a 8-coordinate geometry to two equivalent V, three equivalent Ge, and three equivalent Si atoms. There are one shorter (2.40 Å) and one longer (2.50 Å) V–V bond lengths. All V–Ge bond lengths are 2.54 Å. All V–Si bond lengths are 2.52 Å. In the second V site, V is bonded in a 5-coordinate geometry to three equivalent Ge and two equivalent Si atoms. There are two shorter (2.48 Å) and one longer (2.58 Å) V–Ge bond lengths. Both V–Si bond lengths are 2.65 Å. In the third V site, V is bonded in a 5-coordinate geometry to two equivalent Ge and three equivalent Si atoms. Both V–Ge bond lengths are 2.67 Å. There are two shorter (2.46 Å) and one longer (2.62 Å) V–Si bond lengths. Ge is bonded in a 9-coordinate geometry to nine V atoms. Si is bonded in a 9-coordinate geometry to nine V atoms.
Mn10(GeSi)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Mn sites. In the first Mn site, Mn is bonded in a 5-coordinate geometry to three equivalent Ge and two equivalent Si atoms. There are two shorter (2.44 Å) and one longer (2.51 Å) Mn–Ge bond lengths. Both Mn–Si bond lengths are 2.66 Å. In the second Mn site, Mn is bonded in a 5-coordinate geometry to two equivalent Ge and three equivalent Si atoms. Both Mn–Ge bond lengths are 2.67 Å. There are two shorter (2.42 Å) and one longer (2.54 Å) Mn–Si bond lengths. In the third Mn site, Mn is bonded in a 6-coordinate geometry to three equivalent Ge and three equivalent Si atoms. All Mn–Ge bond lengths are 2.48 Å. All Mn–Si bond lengths are 2.46 Å. Ge is bonded in a 9-coordinate geometry to nine Mn atoms. Si is bonded in a 9-coordinate geometry to nine Mn atoms.
Y10(GeSi)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Y sites. In the first Y site, Y is bonded in a 6-coordinate geometry to three equivalent Ge and three equivalent Si atoms. All Y–Ge bond lengths are 3.08 Å. All Y–Si bond lengths are 3.06 Å. In the second Y site, Y is bonded in a 3-coordinate geometry to three equivalent Ge and two equivalent Si atoms. There are two shorter (2.93 Å) and one longer (3.08 Å) Y–Ge bond lengths. Both Y–Si bond lengths are 3.45 Å. In the third Y site, Y is bonded in a 5-coordinate geometry to two equivalent Ge and three equivalent Si atoms. Both Y–Ge bond lengths are 3.45 Å. There are two shorter (2.93 Å) and one longer (3.09 Å) Y–Si bond lengths. Ge is bonded in a 9-coordinate geometry to nine Y atoms. Si is bonded in a 9-coordinate geometry to nine Y atoms.
Nd10(GeSi)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Nd sites. In the first Nd site, Nd is bonded in a 6-coordinate geometry to three equivalent Ge and three equivalent Si atoms. All Nd–Ge bond lengths are 3.20 Å. All Nd–Si bond lengths are 3.18 Å. In the second Nd site, Nd is bonded in a 3-coordinate geometry to three equivalent Ge and two equivalent Si atoms. There are two shorter (3.04 Å) and one longer (3.19 Å) Nd–Ge bond lengths. Both Nd–Si bond lengths are 3.59 Å. In the third Nd site, Nd is bonded in a 5-coordinate geometry to two equivalent Ge and three equivalent Si atoms. Both Nd–Ge bond lengths are 3.59 Å. There are two shorter (3.04 Å) and one longer (3.19 Å) Nd–Si bond lengths. Ge is bonded in a 9-coordinate geometry to nine Nd atoms. Si is bonded in a 9-coordinate geometry to nine Nd atoms.
V10(GeSi)3 crystallizes in the orthorhombic Fmm2 space group. The structure is three-dimensional. there are five inequivalent V sites. In the first V site, V is bonded in a 6-coordinate geometry to two equivalent Ge and four Si atoms. Both V–Ge bond lengths are 2.60 Å. There are a spread of V–Si bond distances ranging from 2.49–2.74 Å. In the second V site, V is bonded in a 6-coordinate geometry to three Ge and three equivalent Si atoms. There are one shorter (2.53 Å) and two longer (2.60 Å) V–Ge bond lengths. There are one shorter (2.49 Å) and two longer (2.73 Å) V–Si bond lengths. In the third V site, V is bonded in a 6-coordinate geometry to four Ge and two Si atoms. There are two shorter (2.59 Å) and two longer (2.74 Å) V–Ge bond lengths. There are one shorter (2.49 Å) and one longer (2.54 Å) V–Si bond lengths. In the fourth V site, V is bonded in a 6-coordinate geometry to three Ge and three Si atoms. There are one shorter (2.56 Å) and two longer (2.60 Å) V–Ge bond lengths. There are one shorter (2.47 Å) and two longer (2.74 Å) V–Si bond lengths. In the fifth V site, V is bonded in a 6-coordinate geometry to two equivalent V, one Ge, and three Si atoms. There are one shorter (2.38 Å) and one longer (2.43 Å) V–V bond lengths. The V–Ge bond length is 2.56 Å. There are one shorter (2.51 Å) and two longer (2.52 Å) V–Si bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 10-coordinate geometry to eight V and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.41 Å. In the second Ge site, Ge is bonded in a 10-coordinate geometry to ten V atoms. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 10-coordinate geometry to ten V atoms. In the second Si site, Si is bonded in a 10-coordinate geometry to ten V atoms.
U2(GeSi)3 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. U3+ is bonded to six Si4- atoms to form a mixture of distorted edge, face, and corner-sharing USi6 octahedra. The corner-sharing octahedra tilt angles range from 0–88°. There are a spread of U–Si bond distances ranging from 2.88–2.93 Å. There are two inequivalent Ge2+ sites. In the first Ge2+ site, Ge2+ is bonded in a 6-coordinate geometry to six Si4- atoms. There are a spread of Ge–Si bond distances ranging from 2.87–2.94 Å. In the second Ge2+ site, Ge2+ is bonded in a square co-planar geometry to four equivalent Si4- atoms. All Ge–Si bond lengths are 2.92 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 12-coordinate geometry to four equivalent U3+ and four equivalent Ge2+ atoms. In the second Si4- site, Si4- is bonded to four equivalent U3+ and eight Ge2+ atoms to form a mixture of face and corner-sharing SiU4Ge8 cuboctahedra. In the third Si4- site, Si4- is bonded in a 12-coordinate geometry to four equivalent U3+ and four equivalent Ge2+ atoms.
Included in this talk: "Silicon-Germanium as an Enabling Technology for Extreme Environment Electronics" and "Ultra Low Power Mixed-Signal Design Challenges for Moon"