Significant improvement of reverse leakage current characteristics of Si-based homoepitaxial InGaN/GaN blue light emitting diodes

Abstract

The nature of reverse leakage current characteristics in InGaN/GaN blue light emitting diodes (LEDs) on freestanding GaN crystals detached from a Si substrate is investigated for the first time, using temperature-dependent current-voltage (T-I-V) measurement. It is found that the Si-based homoepitaxial InGaN/GaN LEDs exhibit a significant suppression of the reverse leakage current without any additional processes. Their conduction mechanism can be divided into variable-range hopping and nearest neighbor hopping (NNH) around 360 K, which is enhanced by Poole-Frenkel emission. The analysis of T-I-V curves of the homoepitaxial LEDs yields an activation energy of carriers of 35 meV at −10 V, about 50% higher than that of the conventional ones (Ea = 21 meV at −10 V). This suggests that our homoepitaxial InGaN/GaN LEDs bears the high activation energy as well as low threading dislocation density (about 1 × 106/cm2), effectively suppressing the reverse leakage current. We expect that this study will shed a light on the high reliability and carrier tunneling characteristics of the homoepitaxial InGaN/GaN blue LEDs produced from a Si substrate and also envision a promising future for their successful adoption by LED community via cost-effective homoepitaxial fabrication of LEDs.

Understanding the Leakage Mechanisms and Breakdown Limits of Vertical GaN-on-Si p+n−n Diodes: The Road to Reliable Vertical MOSFETs

“…Considering a simplified [ 26 ], theoretical values are close to 3.2 × 10 −5 eV V −1/2 m 1/2 [ 27 , 28 , 29 ]. Depending on the growth conditions in different GaN-based works, ≈ 10 −5 eV V −1/2 m 1/2 are generally reported [ 7 , 24 , 25 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ], as summarized in Figure 5 .…”

“… Comparison of the Poole–Frenkel coefficient (β) ≈ 10 −5 eV V −1/2 m 1/2 obtained from different works on GaN-based systems [ 7 , 24 , 25 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. …”

Challenges and Perspectives for Vertical GaN-on-Si Trench MOS Reliability: From Leakage Current Analysis to Gate Stack Optimization

“…However, these mechanisms are usually not relevant in good vertical designs. As such, bulk conduction mechanisms are more relevant, in particular, variable range hopping (VRH) [54,55,59,[62][63][64][65][66][67][68][69][70][71], Poole-Frenkel emission [59,[63][64][65][66][67][68][69][72][73][74][75][76][77][78], and space charge limited conduction (SCLC) [31,47,53,79].…”

Current Transport Mechanism in Palladium Schottky Contact on Si-Based Freestanding GaN

“…InGaN/GaN multi-quantum well (MQW) light-emitting diodes (LEDs) with a large scalability and a desirable production cost [13][14][15][16].…”

“…However, challenges such as size limits (<6 inch diameter) and manufacturing expenditure have restricted the successful introduction of HVPE freestanding GaN wafers into the commercial community [12]. Recently, we realized Si-based homoepitaxial InGaN/GaN multi-quantum well (MQW) light-emitting diodes (LEDs) with a large scalability and a desirable production cost [13][14][15][16].…”