Silicon-integrated monocrystalline oxide–nitride heterostructures for deep-ultraviolet optoelectronics

Abstract

New opportunities for high-performance CMOS-compatible optoelectronic devices have accelerated the interest in vertically configured device topologies that enable next-generation photonic technologies. Lately, TiN has been identified as a promising refractory metal–ceramic for the hybrid integration of emerging semiconductor materials on a variety of substrates, including Si, MgO, and sapphire. Among these, Si is the least expensive and most commonly used element and substrate material in the semiconductor device industry. Following these examples, a hybrid oxide–nitride–Si stack is proposed and thoroughly investigated herein for its potential use in DUV optoelectronic device applications. The stack comprises β-Ga2O3 thin films grown heteroepitaxially on TiN/Si platforms, wherein the TiN interlayers were heteroepitaxially grown on bulk (100)-oriented Si and act as lattice-mismatched templates and bottom device electrodes. Albeit the relatively large lattice mismatch between Si and TiN, a low in-plane rotation of 3 ∘ revealed that the TiN layers continued to grow as a bulk crystal, paving the way for heteroepitaxial β-Ga2O3 thin films being grown without exhibiting amorphous and metastable phases. DUV photodetectors based on this optoelectronic heterostructure exhibited average peak spectral responsivity and external quantum efficiency levels as high as 249 A/W and 1.23 × 105%, respectively, in the ultraviolet-C regime at an illuminating power density of around 12 µW/cm2.

Low Interface Resistance in Epitaxial β-Ga2O3 Vertical Power Diodes on Silicon (100) Using TiN Buffer

“…TiN’s high electrical conductivity and CMOS compatibility make it an attractive epitaxial buffer for back-contacted vertical power devices. It can be grown under conditions that avoid SiO x formation at the Si-interface.…”

CMOS-compatible MIS–Schottky heterojunctions for plasmonic waveguide modulation

“…6 Moreover, they challenge the traditional trade-offs associated with co-locating high-performance photonics and advanced CMOS electronics on a single chip. 7 Our work paves the way for seamless integration of these technologies, 8,9 opening doors to unprecedented levels of miniaturization and performance in photonic circuits.…”

Facile integration of electro-optic SiO₂/ITO heterointerfaces in MIS structures for CMOS-compatible plasmonic waveguide modulation

“…Such minuscule overlap between the accumulation layer and the plasmonic modal crosssection necessitates an extended device length to obtain reasonable extinction ratio (ER) levels, which inevitably leads back to substantial IL 32 . Moreover, plasmonic modulator designs proposed to date have largely focused on amplitude modulation 33,34 . As such, there is still a need for a compact, low-power modulator design that can avert the strict ER-IL trade-off, better exploit the tunable properties of thin-film optical materials such as ITO, and support different modulation types.…”