# IQE RF LLC, Cornell University and Qorvo Inc present joint paper on vertical junction barrier Schottky diodes

### 07 April 2017

Ming Pan and Xiang Gao, of IQE RF LLC, have published a joint paper with Cornell University and Qorvo Inc in IEEE Transactions on Electron Devices on work on vertical junction barrier Schottky diodes (JBSDs) produced on free-standing gallium nitride (GaN).

The paper entitled “Design and Realization of GaN Trench Junction-Barrier-Schottky-Diodes” detailed work carried out to combine the good characteristics of Schottky barrier diodes and pn diodes (PNDs), using a vertical structure with trenches in p-GaN material reaching down to give Schottky contacts with n-GaN, for power applications.

The experimental observations show promising potential in further improving the performance of Schottky-based GaN power devices.

Abstract:

We present the design principle and experimental demonstrations of GaN trench junction-barrier-Schottky-diodes (trench JBSDs), where the Schottky contact within the patterned trenches is at the same plane as the adjacent p-n junctions. Assisted by the TCAD simulations, the leakage current reduction mechanism is identified as the reduced surface field (RESURF) effect due to the barrier-height difference between the p-n junction and Schottky junction. Design space for the width of stripe-shaped trenches is found to be $< 0.5~\mu \text{m}$ for a drift layer doping level of $10^{15} \sim 10^{16}$ cm $^{-3}$ , while for circular trenches, the size requirement is relaxed. In the fabricated devices with 1– $4~\mu \text{m}$ diameter circular trenches, about 20 times reduction in the reverse leakage is observed with a characteristic shift in the turn-on voltage, which are signatures of the trench JBSD with desired RESURF. The experimental observations are in excellent agreement with the simulation results. This JBSD design shows promising potential in further improving the performance of Schottky-based GaN power devices without the need for ion-implantation or material regrowth.

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