InP-based RTD/HEMT monolithic integration

Abstract

： Monolithic integration of resonant tunneling diodes (RTDs) and high electron mobility transistors (HEMTs) is an important development direction of ultra-high speed integrated circuit. A kind of top-RTD and bottom-HEMT material structure is epitaxied on InP substrate through molecular beam epitaxy. Based on wet chemical etching, metal lift-off and air bridge interconnection technology, RTD and HEMT are fabricated simultaneously. The peak-to-valley current ratio of RTD is 7.7 and the peak voltage is 0.33 V at room temperature. The pinch-off voltage is -0.5 V and the current gain cut-frequency is 30 GHz for a 1.0 µm gate length depletion mode HEMT. The two devices are conformable in current magnitude, which is suitable for the construction of various RTD/HEMT monolithic integration logic circuits.The resonant tunneling diode (RTD) is an ultrahigh speed and ultra-high frequency quantum-transport device with negative differential resistance (NDR) I-V characteristic originating from resonant tunneling effect. RTD is a promising candidate in high-speed integrated circuits since it has been shown to operate at frequencies up to 712 GHz [1] , and also exhibits the fastest switching time (1.5 ps) [2] among semiconductor devices, which is due to its high-peak current density and relatively small capacitance. Moreover, RTD can be vertically integrated to obtain a device with multiple negative differential resistance regions, and can greatly reduce circuit complexity [3][4][5] . These distinct advantages are the driving force for the research of quantum functional devices and circuits using RTDs.Monolithic integration of RTDs and other advanced and well-matured conventional transistors, for example, high electron mobility transistors (HEMTs) or heterojunction bipolar transistors (HBTs), is a practical way to construct ultrahigh-speed circuits. In this mode, RTDs are responsible for the switching function. This mode provides several advantages. Firstly, it allows separate optimization of RTDs and conventional transistors, which is advantageous to reproducibility and uniformity.Secondly, RTDs are used in the core of a circuit, which leads to significant performance enhancement and devices number decrease of various circuits. So far, different logic circuit families based on the RTD/HEMT monolithic integration concept have been proposed, such as compact memory, multivalued logic, oscillators, shift registers and frequency multiplication [6][7][8][9][10][11] .In this paper, a kind of monolithic integration technology of RTD/HEMT based on InP substrate is reported. The RTD/HEMT material structure is epitaxied using molecular beam epitaxy (MBE) technology. RTDs and HEMTs with better performance are fabricated successfully using wet chemical etching, metal lift-off and air bridge interconnection technology.

Spectrofluorometric determination of clonazepam in dosage forms: Application to content uniformity testing and human plasma

“…[10,11] The proposed method depends on the fact that CNP has no native fluorescence because of the powerful quenching effect of its nitro group. [12] However, when the nitro group was reduced to the amino group, this allowed CNP to retain its fluorescence. [13,14] Using fluorescence enhancers, such as CMC the fluorescence intensity of RCNP product increased by a factor of about 100%.…”

A Table-Top Pilot Experiment for Narrow Mass Range Light Cold Dark Matter Particle Searches

“…Novel GaAs/AlGaAs RTD heterostructures with higher sensitivities have been reported in literature which involve a quantum well in the middle [38]. Integrated RTD-HEMT devices have also been demonstrated by incorporating an HEMT junction with electron injection from a RTD structure at the gate [39]. We propose a similar custom-made structure to be incorporated in our design to achieve a gain of around 30-40dB using a combo cryogenic RTD-HEMT device.…”

Based on the CO₂ Gas Shielded Welding Molten Pool Image Edge Detection Algorithm

“…Through the dynamic change of molten pool shape parameters distinguishing weld strength and surface forming surface quality stand or fall of one of the important method, and is one of the hot issues in current research. Currently in order to solve this problem, Literature [1] introduces antimonies corrosion expansion of mathematical morphology operates to after pretreatment weld binary image use for edge extraction. Xue Jiaxiang of South China University of Technology is used of zero-crossing method, no need to set a threshold value, and the zero-crossing detector is a single pixel edge, using Bubble function structure wavelet transform on image [2] .…”