Because I barely know what it means in English, I can't translate it to Spanish, but since no one else has lended a hand, I will try to explain what each phrase or word refers to...
Ionization (I'm going to guess you already know that's 'ionización').
Hole-depleted (depleted refers to the lack of something, la falta de muchos agujeros en la región).
High resistivity (alta resistencia).
Reverse biased (pues, ni idea... reverse es en el sentido contrario, mientras "biased" creo que tiene que ver con sesgar).
Bueno, no soy ningún experto ni tampoco aficionado de estas cosas, entonces, mucha suerte y que veas a mi intento con poca confianza.
Hello - I am not much help with Spanish but I know exactly what this means in English so I will try to explain some of the terms and maybe you will know the Spanish terms
Reverse biased - I am assuming you are dealing with a pn junction. Reverse biased means +ve external voltage applied to n-type material and -ve external voltage applied to the p-type material. So your junction is "reverse biased" when the external voltages are like this.
Hole-depleted - In normal p-type material (with no external voltage) there is an abundance of 'holes' - they can be thought of as positive charges (in reality they are the absence of an electron). When you apply a reverse bias to a pn junction (eg a diode) these excess holes will be swept out of the p material and you will be left with no charge carriers in the p or n material. In effect the depletion layer widens beyond its normal size to the width of the diode.
I think what is being explained in your case is that ionizations ( generation of a hole - electron pair ) lower the effective resistance of your junction.
Resistivity is a constant for any material (symbol greek 'rho' ρ) defined
R = ρL/A (R=resistance ohms, ρ=resistivity, L=length metres, A=area (metres squared). You may have seen this in an experiment for calculating the resistivity of a length of wire for example.
Conductivity is the inverse of resistance ( if resistance is high then the conductivity is low and vica versa)
OK. Attempting to translate this reminds me of the movie "Fools rush in" (Los insensatos se lanzan). I have no idea what any of it means, but I tried to assign each word a grammatical role and I came up with the following Spanish mirror nonsense sentence .
Ionizaciones en la región de alta resistencia reducida de hoyos de una conductibilidad de aumento tipo semiconductor predispuesta al sentido contrario.
I must confess it's the first time I feel like a total fool translating something. . Saniredondo, you're a threat to everyone's sanity.