High‐Quality Bulk β‐Ga₂O₃ and β‐(Al_xGa_1−x)₂O₃ Crystals: Growth and Properties

Abstract

A method for the growth of high‐quality gallium oxide (β‐Ga2O3) bulk crystals from the melt is developed. The influence of the atmosphere in the process zone on the stability of growth and the quality of Czochralski grown crystals is studied. The structural properties of the crystals obtained are investigated. Samples of gallium oxide substrates are demonstrated. The possibility of growing bulk crystals of solid‐solution oxides (AlxGa1–x)2O3 is tested.

State-of-the-Art β-Ga2O3 Field-Effect Transistors for Power Electronics

“…The feasibility of using the CZ method with Ir crucibles for growing β-Ga 2 O 3 single crystals was demonstrated in 2000, 5 and major improvements have been made since 2010. 49 − 55 The starting material, 5N-grade β-Ga 2 O 3 powder, is first placed in the Ir crucible, which is heated by the surrounding radiofrequency (RF) inductor to form the β-Ga 2 O 3 melt. A seed crystal is introduced into the melt and then slowly pulled up (1 to 2 mm h –1 ) while rotating (5 to 10 rpm).…”

Steady-state and transient electronic transport properties of β-(Al x Ga1–x )2O3/Ga2O3 heterostructures: An ensemble Monte Carlo simulation

“…Parameter (eV)/(m 0 ) Simulated value Experimental value Band gap (x = 0) 4.889 4.9 [18] Band gap (x = 0.125) 5.001 4.96 (x = 0.12) [27] Band gap (x = 0.188) 5.110 5.20 (x = 0.2) [12] Band gap (x = 0.313) 5.393 5.32 (x = 0.31) [27] Effective mass (0.274, 0.433, 0.642) 0.28 (lowest valley) [28] (x = 0) (Γ , Y Γ , M) Effective mass (0.295, 0.585, 0.719) 0.294 (lowest valley) [17] (x = 0.125) (Γ , Y Γ , M) Effective mass (0.306, 0.729, 0.849) 0.301 (lowest valley) [17] (x = 0.188) (Γ , Y Γ , M) Effective mass (0.333, 0.858, 0.978) 0.313 (lowest valley) [17] High-frequency dielectric constant 3.57ε 0 [13] Mass density 5880 kg•m −3 [30] Sound velocity 6880 m•s −1 [4] Acoustic deformation potential 6.9 eV [4] Polar optical phonon energy 48 meV [4,29] Average roughness height 0.45 nm [13] Horizontal correlation length 4.7 nm [13] Dislocation density 10 5 cm −2 [10] In our MC simulation, the critical features of the conduction bands are the Γ , Y Γ , and M valleys. The quantization effect is considered only in the Γ valley with the five lowest subbands.…”

“…The quantization effect is considered only in the Γ valley with the five lowest subbands. The material parameters [4,10,13,29,30] used in the calculations are listed in Table 2. To compute the scattering rates of the 2DEG, the energy levels and wave functions are achieved by self-consistently solving the Schrödinger-Poisson equations.…”

“…[1,2] β -Ga 2 O 3 has the most stable crystal structure among the five phases (α, β , γ, ε, and δ ) of Ga 2 O 3 . [3] β -Ga 2 O 3 also has excellent intrinsic material properties, including a large breakdown field strength of ∼ 8 MV•cm −1 , [4] a high Baliga figure of merit of ∼ 3444, [5] and the availability of highquality native substrates grown directly from the melt. [4] β -(Al x Ga 1−x ) 2 O 3 is a ternary alloy of β -Ga 2 O 3 with a tunable band gap ranging from 4.8 eV to 6 eV.…”

“…[3] β -Ga 2 O 3 also has excellent intrinsic material properties, including a large breakdown field strength of ∼ 8 MV•cm −1 , [4] a high Baliga figure of merit of ∼ 3444, [5] and the availability of highquality native substrates grown directly from the melt. [4] β -(Al x Ga 1−x ) 2 O 3 is a ternary alloy of β -Ga 2 O 3 with a tunable band gap ranging from 4.8 eV to 6 eV. [6,7] In particular β -(Al x Ga 1−x ) 2 O 3 /Ga 2 O 3 heterostructures can be formed, [8] and the introduction of ternary alloys and the formation of heterostructures can significantly increase the number of possible applications and the performance of devices.…”