Space–Charge Profiles and Carrier Transport Properties in Dopant‐Free GaN‐Based p‐n Junction Formed by Distributed Polarization Doping

Abstract

Herein, the operation of dopant‐free GaN‐based p‐n junctions formed by distributed polarization doping (DPD) is experimentally demonstrated and their space charge profiles and carrier transport properties are investigated. The device exhibits ideal space charge profiles explained by polarization effects and demonstrates the excellent controllability of DPD. In addition, it shows rectification and electroluminescence under forward‐biased conditions. The carrier transport properties could be explained by the conventional recombination/diffusion model used for impurity‐doped p‐n junctions. Repeatable breakdowns are also observed in all devices and the temperature‐dependent breakdown voltages reveal that the breakdowns are caused by avalanche multiplication, which is also the same as those reported in impurity‐doped GaN p‐n diodes. These results indicate that DPD is a promising doping technology for GaN‐based power devices overcoming any issues associated with conventional impurity doping.

Polarization induced doping for carrier transport in graded III-nitride layers: a simulation study

“…Adjacent to the graded regions, there are unintentionally doped (uid) GaN layers of 50 nm and 100 nm thickness on the p-and n-sides, respectively. These uid-and the graded AlGaN layers are assumed to have N D = 10 16 cm −3 n-type (Silicon) doping on the right side of the junction and N A = 10 16 cm −3 p-type (Magnesium) doping on the left side of the junction, which is consistent with SIMS characterization in [7]. Simulations with different background impurity densities and types have been made, and show no effect if their densities are below the polarization charge density.…”

“…In [7] a pn-diode with a junction defined by graded AlGaN layers has been demonstrated. Solving the system of Poisson-and continuity-equations for electrons and holes in two dimensions, the current-voltage characteristics and the internal charge distribution are calculated using the Synopsys Sentaurus [8].…”

“…Next, the current versus voltage characteristics are simulated, and compared to the experimental data published in [7]. From the mobile and immobile carrier distribution, a rectifying behaviour can be expected.…”

Thermal Boundary Conductance of Direct Bonded Aluminum Nitride to Silicon Interfaces

“…4−8 In addition to having good thermal properties, AlN is a common material in microelectronics with well-known growth methods expediting their integration to new processes. Recently, AlN-based field-effect transistors 9 and p−n diodes 10 have been demonstrated to prove that AlN-based devices have practical appeal beyond the improved thermal properties.…”

Demonstration of AlGaN-on-AlN p-n Diodes with Dopant-free Distributed Polarization Doping

“…This approach presents a promising solution to the challenges of conductivity control in AlN-based materials. To date, we have extensively studied GaN-based vertical p-n diodes formed by dopant-free DPD and demonstrated excellent electrical properties such as ideal breakdown electric field, high hole mobility, as well as longer electron lifetime and larger diffusion coefficient than those of p-GaN:Mg [16]- [18]. Moreover, our group employed DPD for the p-type cladding layer of an AlN-based laser diode to increase its conductivity and transparency.…”