Layered boron nitride as a release layer for mechanical transfer of GaN-based devices

Abstract

Nitride semiconductors are the materials of choice for a variety of device applications, notably optoelectronics and high-frequency/high-power electronics. One important practical goal is to realize such devices on large, flexible and affordable substrates, on which direct growth of nitride semiconductors of sufficient quality is problematic. Several techniques--such as laser lift-off--have been investigated to enable the transfer of nitride devices from one substrate to another, but existing methods still have some important disadvantages. Here we demonstrate that hexagonal boron nitride (h-BN) can form a release layer that enables the mechanical transfer of gallium nitride (GaN)-based device structures onto foreign substrates. The h-BN layer serves two purposes: it acts as a buffer layer for the growth of high-quality GaN-based semiconductors, and provides a shear plane that makes it straightforward to release the resulting devices. We illustrate the potential versatility of this approach by using h-BN-buffered sapphire substrates to grow an AlGaN/GaN heterostructure with electron mobility of 1,100 cm(2) V(-1) s(-1), an InGaN/GaN multiple-quantum-well structure, and a multiple-quantum-well light-emitting diode. These device structures, ranging in area from five millimetres square to two centimetres square, are then mechanically released from the sapphire substrates and successfully transferred onto other substrates.

Single Crystal Gallium Nitride Nanomembrane Photoconductor and Field Effect Transistor

“…[ 5 ] There have also been efforts and demonstrations in separating µm-thick GaN device structures from substrates using laser liftoff, [ 6 ] chemical liftoff, [ 7 ] electrochemical liftoff, [ 8,9 ] and mechanical liftoff on suitable buffer layers. [ 10,11 ] These works open the way for vertical device confi guration but fall short in the pursuit of ultrathin (<500 nm), mechanically fl exural membranes. As the freestanding layer thickness decreases to below 500 or even 100 nm, the fl exural rigidity of the layer is expected to decrease dramatically.…”

Role of hydrogen carrier gas on the growth of few layer hexagonal boron nitrides by metal-organic chemical vapor deposition

“…Kobayashi et al, demonstrated MOCVD-grown h-BN as a releasing layer for transferring the GaN-based LED epitaxial structure grown on the h-BN onto foreign flexible substrates. [15][16][17] Recently, Q. S. Paduano et al, reported self-terminating effect in MOCVD growth of h-BN 18 and investigated effects of growth parameters including reactor pressure, and V/III ratio, defined as molar flow ratio between NH 3 and triethylborane (TEB) which are source of nitrogen and boron respectively, on thickness of MOCVD-grown h-BN. 19 X.…”

Nature of exciton transitions in hexagonal boron nitride

“…With an energy bandgap around 6.5 eV, h-BN is emerging as an important semiconductor material. [3][4][5][6][7] With its unique physical properties including high temperature and chemical stability, h-BN has potential applications in high temperature/power electronic device applications. P-type conductivity seems to be more easy to realize in h-BN than in AlN, which reveals the potential of h-BN for deep UV emitter and detector applications.…”