Extended Data Fig. 2: ToF-SIMS.
From: Using both faces of polar semiconductor wafers for functional devices
The top row shows the group III element ratios in the LED (left) and HEMT (right) heterostructures and the bottom row shows the Mg, O, Si and C impurity densities for the respective heterostructures. The detection limits for the impurity densities are [Mg] ≈ 1–2 × 1016 cm−3, [O] ≈ 3–4 × 1016 cm−3, [Si] ≈ 7–8 × 1015 cm−3 and [C] ≈ 1 × 1016 cm−3. There is no noticeable interdiffusion of dopants or group III broadening of the metal-polar LED layers after growth of the N-polar HEMT, indicating that interface and doping control is not affected by secondary growth.
