Salman Latif

Silicon Germanium CMOS Optoelectronic Switching Device: Bringing Light to Latch

We propose a novel semiconductor optoelectronic (OE) switch that is a fusion of a Ge optical detector and a Si metal-oxide-semiconductor (MOS) field-effect transistor (FET). The device operation principle is investigated, and the performance is explored by simulations. The proof of principle is demonstrated by experiments. The use of Ge enables operation in standard telecommunication wavelengths, in addition to providing the surrounding Si circuitry with noise immunity from signaling. The transconductance of the FET provides amplification, and an experimental current gain of up to 1000 is demonstrated. A complementary function is shown by tailoring the doping profiles. The circuit performance of a complementary pair using the International Technology Roadmap for Semiconductors values for the 150-nm node is evaluated by simulation, yielding ~100-ps cycle times. The switch can be fabricated in the nanoscale regime along with a high-performance Si complementary MOS. A very low capacitance can be achieved due to the isolation of the detection region from the current drive. OE conversion that is performed with such a compact device offers the potential of inserting light at the latch level in a microprocessor.

Pump-probe measurements of CMOS detector rise time in the blue

This paper proposes the use of shorter wavelengths and monolithic integration for chip-to-chip and on-chip optical communication. The promise of monolithic detectors for high-speed interconnection is demonstrated through experimental measurements and matching simulations. Responsivities >0.06 A/W and transit-time-limited response can be expected in the blue from planar p-i-n silicon-on-insulator (SOI) detectors.

SiGe optoelectronic metal-oxide semiconductor field-effect transistor

We propose a novel semiconductor optoelectronic switch that is a fusion of a Ge optical detector and a Si metal-oxide semiconductor field-effect transistor (MOSFET). The device operation is investigated with simulations and experiments. The switch can be fabricated at the nanoscale with extremely low capacitance. This device operates in telecommunication standard wavelengths, hence providing the surrounding Si circuitry with noise immunity from signaling. The Ge gate absorbs light, and the gate photocurrent is amplified at the drain terminal. Experimental current gain of up to 1000x is demonstrated. The device exhibits increased responsivity (approximately 3.5x) and lower off-state current (approximately 4x) compared with traditional detector schemes.

Femtosecond carrier dynamics in Ge/SiGe quantum wells

We resolve photoinduced changes in carrier populations of Ge SiGe quantum wells using femtosecond pump-probe spectroscopy. Absorption transients 400 fs indicate rapid GammararrL intervalley scattering that may explain exciton linewidth and suggest saturable absorber applications.

Novel optically-controlled optical switch based on intimate integration of surface-normal photodiode and waveguide electroabsorption modulator for wavelength conversion

For optical-electronic-optical (o-e-o) conversion without the use of conventional electronics, we introduce a novel, highly-integrated, chip-scale, optically-controlled optical switch that incorporates a surface-normal photodiode (PD) and a waveguide electroabsorption modulator (EAM) on the same substrate. Such an integrated optical switch avoids the difficulties and the limitations of ordinary o-e-o conversion, and eliminates the need for separate packaging of its individual parts.

Plasmonic device in Si CMOS

Using Al metal, here for the first time, we demonstrate plasmonic devices fabricated on a commercial complementary metal-oxide-semiconductor (CMOS) chip, paving the way for plasmonics to become the next wave of chip-scale optoelectronic technology.

Novel Si-based CMOS Optoelectronic Switching Device Operating in the Near Infrared

A novel, high performance optoelectronic switch is introduced. The device is a Si-MOSFET with Ge gate that can be fabricated at the nanoscale with very low capacitance. Current gain of up to 1000times is demonstrated.

Novel Si-based Optoelectronic Switching Device: Light to Latch

A novel, high performance optoelectronic switch is introduced. The device is a Si- MOSFET with Ge gate that can be fabricated at the nanoscale with very low capacitance. Current gain of up to 1000times is demonstrated.

Rise-Time Measurements of Low Capacitance CMOS Detectors Using a Pump-Probe Technique

Optical interconnect and clocking applications require low capacitance, high speed, CMOS-compatible photodetectors. We characterize the small-signal pump-probe response of Silicon on Sapphire CMOS compatible detectors showing response ~ 35 ps.