High-gain GaN impact-ionization avalanche transit-time (IMPATT) diodes have been fabricated and experimentally characterized. The devices feature a "Hi-Lo" doping profile design; temperature-dependent reverse I - V measurement verified impact ionization avalanche as the dominant breakdown mechanism. IMPATT operation was confirmed, with reflection gain observed between 19.3 and 50.1 GHz using pulsed bias conditions of -175 V and current density of 7.6 kA/cm(2). Apeak reflection gain of 1.97 dB was observed around 30.8 GHz. On-wafer S-parameter measurements revealed a large negative differential resistance (NDR) of -992 Omega , comparable to state-of-the-art Si IMPATT diodes. The RF output power density is projected to be 40.3 kW/cm(2) at 35 GHz. The short-pulse on-wafer S-parameter-based measurement technique used here facilitates direct extraction of device impedance, providing insights into the optimal impedance matching of the peripheral resonant circuit and the appropriate operating frequency. Temperature-dependent characterization shows that the avalanche frequency has a much stronger dependence on current density rather than bias voltage. Therefore, biasing with a current source is preferred compared to a voltage source for stable operation in applications. The maximum operating frequency is found to increase at higher temperatures, possibly due to a decrease in the series resistance associated with the anode's p-contact resistance. These devices are promising for high-power, high-efficiency K-band to V-band signal generation across a broad temperature range.

High-gain GaN impact-ionization avalanche transit-time (IMPATT) diodes have been fabricated and experimentally characterized. The devices feature a "Hi-Lo" design; temperature dependent reverse I-V measurement verified impact ionization avalanche as the dominant breakdown mechanism. IMPATT operation was confirmed, with reflection gain observed between 20 GHz and 45 GHz using pulsed bias conditions of -177 V and current density of 7.5 kA/cm(2). A peak reflection gain of 1.4 dB was observed around 30 GHz. On-wafer S-parameter measurements revealed large negative differential resistance of -803 Omega, comparable to state of the art Si IMPATT diodes. The RF output power density is projected to be 42.1 kW/cm(2) at 35 GHz. The short-pulse on-wafer S-parameter-based measurement technique used here facilitates direct extraction of device impedance, providing insights into the optimal impedance matching of the peripheral resonant circuit and the appropriate operating frequency. These devices are promising for high-power, high-efficiency K-band to V-band signal generation.

We report the experimental characterization and theoretical analysis of high-frequency GaN IMPATT diodes featuring a Hi-Lo doping profile. On-wafer small-signal measurements of reflection gain over frequency and temperature confirm IMPATT operation covering Ka through V bands. Temperature-dependent reverse I–V measurements also confirmed avalanche breakdown as the dominant breakdown mechanism. Under a pulse bias of −175 V and current density of 7.6 kA/cm2, the fabricated IMPATT diode exhibited gain between 19.3 and 50.1 GHz, with peak gain of 1.97 dB at ∼30.8 GHz. Temperature dependent characterization revealed that while the bias voltage required for operation at a given frequency changes significantly with temperature, consistent and stable performance can be achieved using a current source for biasing. For a fixed current density, both the avalanche frequency and device impedance remained relatively stable over a broad ambient temperature range. For use as a free-running oscillator, the minimum required Q for the external resonator was found to be less than 3.6, which is well within the range of what can be achieved in practice at these frequencies. Theoretical predictions of avalanche frequency were conducted and showed good agreement with the measured avalanche frequency, facilitating precise design of oscillators for applications. The fabricated IMPATT diodes demonstrate significant potential for high-power and high-efficiency signal generation from K-band to V-band across a wide temperature range.

GaN and related semiconductors have become an increasingly prominent material for a wide range of active and passive devices from optoelectronics to high frequency and power electronics as well as photocatalysis. Regardless of the application, anisotropic etching is required for micro and nano structuring, currently performed by reactive ion etching (RIE). Alternately, metal-assisted chemical etching (MacEtch) is an open-circuit plasma-free anisotropic etching method that has demonstrated high aspect ratio device structures devoid of plasma-induced damage found in RIE. This paper presents an in-depth study of the ensemble electrochemical mechanisms that govern the photo-enhanced MacEtch process of GaN and related heterojunctions. Through in-depth experimental investigations, modeling and simulations, the effects of local cathode and anode design, energy-band alignments, and solution chemistry on MacEtch are correlated with the underlying electronic mechanisms of carrier generation, annihilation, transport, and extraction, establishing a fundamental framework for parametrized prediction of system behavior. These findings carry profound implications for tailored design of photoelectrochemical processes employed not just for uniformly etching wide/ultrawide bandgap materials but more broadly for semiconductor-based photocatalytic reactions in general. One-pot photo-enhanced MacEtching of AlInGaN multi-heterojunction device structures including superlattices and multi-quantum wells are demonstrated.

We report the direct observation of radio-frequency negative differential resistance, via on-wafer S-parameter measurements, in GaN-based impact ionization avalanche transit time (IMPATT) diodes. Clear signatures of reflection gain are observed from 18.7 to 30.6 GHz. These observations have been made possible by suppressing the reverse leakage current (and thereby parasitic shunt conductance) by optimization of the fabrication process, in conjunction with the use of pulsed measurements to suppress device self-heating. Consistent with avalanche-dominated behavior, the measured DC reverse bias current–voltage measurements show a positive temperature coefficient of breakdown. For the high-frequency on-wafer characterization, pulsed-bias S-parameter measurements with low (0.0067%) duty cycle were used to mitigate thermal effects. The measured avalanche frequency aligns closely with theoretical predictions based on Gilden and Hines' small signal model [Gilden and Hines, IEEE Trans. Electron Devices ED-13(1), 169–175 (1966)], measured impact ionization coefficients [Cao et al., Appl. Phys. Lett. 112(26), 262103 (2018)], and experimental saturation velocity measurements [Bajaj et al., Appl. Phys. Lett. 107(15), 153504 (2015)]; this excellent agreement confirms IMPATT operation and provides insights needed to further optimize device performance.

First-line immunotherapy has been shown to significantly improve survival in patients with advanced/metastatic NSCLC. The anti-PD-1 antibody pembrolizumab alone showed superior efficacy over chemotherapy in untreated patients with advanced NSCLC and PD-L1 expression ≥50%, yet most patients will eventually experience progression. Datopotamab deruxtecan (Dato-DXd) is an antibody-drug conjugate composed of a humanized anti-TROP2 IgG1 monoclonal antibody covalently linked to a topoisomerase I inhibitor payload via a plasma-stable, tetrapeptide-based, cleavable linker.

BACKGROUND:Amivantamab has been approved for the treatment of patients with advanced non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertions who have had disease progression during or after platinum-based chemotherapy. Phase 1 data showed the safety and antitumor activity of amivantamab plus carboplatin-pemetrexed (chemotherapy). Additional data on this combination therapy are needed. METHODS:In this phase 3, international, randomized trial, we assigned in a 1:1 ratio patients with advanced NSCLC with EGFR exon 20 insertions who had not received previous systemic therapy to receive intravenous amivantamab plus chemotherapy (amivantamab-chemotherapy) or chemotherapy alone. The primary outcome was progression-free survival according to blinded independent central review. Patients in the chemotherapy group who had disease progression were allowed to cross over to receive amivantamab monotherapy. RESULTS:A total of 308 patients underwent randomization (153 to receive amivantamab-chemotherapy and 155 to receive chemotherapy alone). Progression-free survival was significantly longer in the amivantamab-chemotherapy group than in the chemotherapy group (median, 11.4 months and 6.7 months, respectively; hazard ratio for disease progression or death, 0.40; 95% confidence interval [CI], 0.30 to 0.53; P<0.001). At 18 months, progression-free survival was reported in 31% of the patients in the amivantamab-chemotherapy group and in 3% in the chemotherapy group; a complete or partial response at data cutoff was reported in 73% and 47%, respectively (rate ratio, 1.50; 95% CI, 1.32 to 1.68; P<0.001). In the interim overall survival analysis (33% maturity), the hazard ratio for death for amivantamab-chemotherapy as compared with chemotherapy was 0.67 (95% CI, 0.42 to 1.09; P = 0.11). The predominant adverse events associated with amivantamab-chemotherapy were reversible hematologic and EGFR-related toxic effects; 7% of patients discontinued amivantamab owing to adverse reactions. CONCLUSIONS:The use of amivantamab-chemotherapy resulted in superior efficacy as compared with chemotherapy alone as first-line treatment of patients with advanced NSCLC with EGFR exon 20 insertions. (Funded by Janssen Research and Development; PAPILLON ClinicalTrials.gov number, NCT04538664.).

Amivantamab, an EGFR-MET bispecific antibody, is approved for the treatment of advanced EGFR ex20ins NSCLC patients (pts) that have progressed on platinum-based chemotherapy. In this exploratory analysis, we investigated the patterns of progression on amivantamab therapy among pts in this population.

The CHRYSALIS study (NCT02609776) is an ongoing Phase 1 trial evaluating the combination of amivantamab (ami) and lazertinib (laz) in patients with epidermal growth factor receptor (EGFR)-mutant (EGFRm) NSCLC. As previously reported, all 20 patients in the treatment-naive cohort who received ami + laz achieved a partial response (overall response rate of 100.0% [95% CI, 83.2-100.0]) after a median follow-up of 7 months (Cho Ann Oncol 2021; 31:S813; 1258O). Herein, we present updated results from this treatment-naive cohort.

First-line treatment with immunotherapy plus platinum-based chemotherapy has significantly improved survival in patients with advanced/metastatic NSCLC; however, many patients progress within 1 year. Datopotamab deruxtecan (Dato-DXd) is an antibody-drug conjugate (ADC) consisting of a humanized anti-TROP2 IgG1 monoclonal antibody attached to a topoisomerase I inhibitor payload via a tetrapeptide-based cleavable linker. Preclinical studies suggest that combining Dato-DXd with platinum-based chemotherapy and an anti–PD-1/PD-L1 inhibitor may result in enhanced antitumor activity and improved clinical outcomes.

Few treatment options are available for patients with advanced/metastatic NSCLC without actionable genomic alterations that has progressed on standard therapies. Datopotamab deruxtecan (Dato-DXd) is an antibody-drug conjugate consisting of a humanized anti-TROP2 IgG1 monoclonal antibody attached to a topoisomerase I inhibitor payload via a tetrapeptide-based cleavable linker. Results from a phase 1 study (TROPION-PanTumor01) in advanced/metastatic NSCLC support evaluation of Dato-DXd as a potential treatment option for these patients.

Despite sharing similar tumor biology to other epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) tumors, no targeted therapies have been approved for NSCLC harboring EGFR Exon 20 insertion mutations (Exon20ins). The standard of care remains platinum-based chemotherapy for the front-line, with no clear subsequent options available. Amivantamab (JNJ-61186372) is a novel, fully human EGFR-MET bispecific antibody with immune cell-directing activity that targets activating and resistance EGFR mutations, as well as MET mutations and amplifications, and has received FDA Breakthrough Therapy Designation for the treatment of patients with EGFR Exon20ins NSCLC after platinum-based chemotherapy.