Showing papers on "IMPATT diode published in 2023"

An integrated millimeter-wave and photonic system-on-chip solution with extended ft and fmax: Can optoelectronic RF CMOS completely replace silicon photonics?

Abstract: Millimeter wave semiconductor devices (Tunnel Diode, GUNN, IMPATT diode, BARITT diode) generate microwaves for a wide range of frequencies. A millimeter wave MOSFET consists of an NMOSFET or FINFET, and a millimeter wave generating diode (an adjustable resistor – in the case of a GUNN diode) in the drain region. The MOSFET and the millimeter wave diode are integrated as one device. When a gate voltage and a drain voltage are applied, the MOSFET is turned on, so as the GUNN diode, which generates RF signals modulated by the high-frequency signals from the gate. If the MOSFET is turned off, the Tunnel Diode / GUNN diode is also off. For an embedded IMPATT or BARITT diode, the millimeter wave device won’t be turned off by the MOSFET, due to the avalanche process, but the output signal is modulated by both the gate and drain voltages. An Optoelectronic or Photonic CMOS field effect transistor includes a built-in laser in either or both of the source and drain regions, or in the well regions (for Depletion-mode CMOS lasers), and multiple photon sensors in the channel or well regions. The MOSFET, lasers, and photon sensors are fabricated as one integral transistor. When the MOSFET is on, the lasers are turned on. When the MOSFET is off, the lasers are off. The Photonic CMOS is light emitting device. Traditional CMOS transistors are not. There are various types of Millimeter wave and Photonic MOSFETs. In this paper, we will explore the advantages of these devices, including improved cutoff frequency (ft or fmax), and signal to noise ratio (S/N) for RF CMOS, and higher Ion / Ioff for RF ASICs. We would also like to look into the possibility of completely replacing the Silicon Photonics, which forms silicon-based IC and lasers separately but on the same wafer- with nonlinear optoelectronic and millimeter wave CMOS, due to improve flexibility, much higher speed, and lower costs.

Bias Current Modulation of DC and RF Properties of Al m Ga 1‐m ∼GaN Heterojunction IMPATT at Sub‐Millimeter Wave Frequency

Abstract: Large signal RF properties of double drift region (DDR) Impact Avalanche Transit Time (IMPATT) device based on AlmGa1-m∼GaN heterojunction (HT) are investigated and their variation with bias currents has been presented here. These RF properties and their modulation will significantly validate the acceptability of the particular HT in the sub-millimeter wave frequency domain. Avalanche noise plays the prime ground for making the IMPATT diode basically noisy and tunneling decays the performance of the device, as we move towards the higher frequency range like the sub-millimeter frequency. These setbacks can be done with if the homojunction (HM) is replaced by heterojunction. This authenticates the choice of heterojunction over homojunction. Here, the author takes 500 GHz as the frequency of concern in the sub-millimeter wave range. Here, two complementary heterojunctions of AlmGa1-m∼GaN is taken with m = 0.4 or the mole fraction of Al in the alloy being 40% and their RF results are compared with two homojunctions of GaN and AlGaN for double drift region (DDR) IMPATT diode. Outcomes indicate that HT diodes surpass the high-frequency performance of HM diodes if compared on the basis of dc to RF conversion efficiency and output power due to the influence of large amplitude ac signal. It is also observed that with increasing bias voltage dependent current, which is varied from 20 × 108 to 40 × 108 Am−2, the efficiency of conversion together with the power output increases. These results will be very important for further research in this domain.

Junction Diameter Dependence of Oscillation Frequency of GaN IMPATT Diode Up to 21 GHz

Abstract: An experimental study on the effects of junction capacitance and current density on the oscillation characteristics of GaN single-drift-region (SDR) impact ionization avalanche transit-time (IMPATT) diodes were carried out using GaN p+-n abrupt junction diodes of various diameters, 200, 150, and 100 μm, with a depletion layer width of 2 μm. The fabricated diodes showed a clear avalanche breakdown at 315 V and a pulsed microwave oscillation with a peak output power exceeding 30 dBm. The oscillation frequency depended on junction diameter and current density. It was widely modulated from 8.56 to 21.1 GHz with decreasing junction diameter and increasing current density. The highest oscillation frequency was obtained with a current density of 13.8 kA/cm2 and a junction diameter of 100 μm. A numerical calculation based on Read-type small-signal theory was carried out and found to well explain the experimental results.