A comparative study of the passivation films on AlGaAs/GaAs heterojunction diodes and bipolar transistors

Effect of surface states on the electrical properties of MBE grown modulation doped AlGaAs/GaAs

“…Previous investigations of dielectric passivation of GaAs-bulk and GaAs-based devices have been reported. For example, Kapila 14 and Hwang 15 implemented SiN x and SiO x passivation methods on GaAs/AlGaAs HBTs. They found that passivated samples presented improved I-V response.…”

Low-Dark-Current Heterojunction Phototransistors with Long-Term Stable Passivation Induced by Neutralized (NH4)2S Treatment

“…A significant factor degrading the performance of GaAsbased minority-carrier devices is surface leakage resulting from the large surface recombination velocity and the high density of the surface state. Surface leakage particularly degrades the low-bias performance of heterojunction bipolar transistors (HBTs) [1][2][3][4][5][6][7][8][9][10][11] and the low-power optical performance of heterojunction phototransistors (HPTs). 12) These defects mainly result from native surface oxides, the nature of dangling bonds, and the disruption of the crystal lattice at the etched mesa edge.…”

“…Reliable surface-passivation techniques have hence become an important issue in developing a good device performance. The use of dielectric materials (SiO 2 and Si 3 N 4 ) 1,2) and depleted emitter passivation ledges 3,4) to cover the exposed surface have been demonstrated. In addition, passivating the surface by chemical treatments with compounds such as Na 2 S, S 2 Cl 2 , (NH 4 ) 2 S, and (NH 4 ) 2 S x [5][6][7][8][9][10][11] is also a popular method.…”

Promoted Potential of Heterojunction Phototransistor for Low-Power Photodetection by Surface Sulfur Treatment

“…Reliable surface passivation techniques hence became an important issue. Covering the surface with dielectric materials, 4,5 passivating the surface via performing chemical treatments, [6][7][8][9][10][11][12] and passivating the extrinsic base surface by emitter ledge structure [13][14][15] are commonly used methods. Advantages including ͑i͒ suppression of the surface recombination effects, which causes a promoted current gain and possible operation at low collector current regimes, ͑ii͒ reduction of sheet resistance and specific contact resistance, and ͑iii͒ improved thermal stability have been demonstrated for HBTs with this surface passivation.…”